THE USE OF 
THE MICROSCOPE 
IN THE 
DIFFERENTIAL DIAGNOSIS 
—OF— 
yVLoRBiD Growths, 
With a New Method for Determining the Diagnosis, Prognosis and 
Treatment of 
TUMORS AND CANCERS 
S. FLEET SPEIR, M.D. 
Surgeon to the Brooklyn City Hospital: Surgeon to the Brooklyn Eye and Ear 
Infirmary ; Surgeon to the Tumor and Cancer Department of the Brooklyn 
Dispensary ; Fellow of the New York Academy of Medicine ; 
Member of the N. T. Pathological Society. &c. 
Bead before the New York Academy of Medicine, April 6th, 1871 ; and 
by authority of the Academy published preparatory to its 
discussion at the regular meeting, April 20th. 
fttfo |lnrk: 
Office of The Medical Gazette, 109 Nassau Street. 
1871/ Examples of compound Cancer cell EC 
Examples of imple Cancer cells'"as they 
are usually represented 
Examples Cancer cells as described 
in this paper Mr. President, Gentlemen, Fellows of the Academy : 
The subject to which I am permitted to invite 
your attention is— 
The Use of the Microscope in the Differential 
Diagnosis of Morbid Growths; the Characters and 
Causes of Cancer, with a New Method for Determin- 
ing the Diagnosis, Prognosis and Treatment of 
Tumors and Cancers. 
In these days of microscopy, when almost every 
physician resorts more or less to the use of the micro- 
scope as a means of diagnosis, and the pathological 
resources of the profession are so great that a com- 
prehensive knowledge of morbid growths seems to 
be within the reach of all, is it not strange that some 
absolute and definite characteristic has not been at- 
tributed to the cells of that growth (cancer) which, be- 
fore the application of the microscope, had puzzled 
all observers, and which even now seems to baffle 
the efforts of practical men to perceive of what real 
benefit the application of the microscope has been 
in solving the question of the malignity of morbid 
growths ? 
Most surgeons or physicians have little need of the 4 
aid of a microscope to determine a cancer when it is 
fully developed. The naked eye, and the history of 
the case, are sufficient to decide the question at 
once; and the recognition of the “mother cell,” or 
“ compound cancer cell,” is only looked for to corrob- 
orate the preconceived opinion. 
That the “ compound cancer cell,” or poly-nucle- 
ated cell, is characteristic of cancer there can be no 
doubt, but that it is to be found in all cancers is cer- 
tainly not true: it belongs to a certain stage of de- 
velopment of most cancers. In other, stages of 
growth it is not found, and in its stead we find, as a 
constant element, a different form of cell, which to 
me has been sufficient to aid very positively in the 
diagnosis of cancer by the use of the microscope, as 
well as to determine the degree of malignity of a 
given tumor, in its early stage of development. 
During the past ten years, my opportunities for 
pathological observation, and the microscopical study 
of morbid growths have been considerable, and 1 
feel that it is my duty as well as a pleasure to place 
upon record a few points which have seemed to me 
to be of importance in the study of morbid growths. 
Having felt the need of something more than the 
current theories of the day to solve the problems 
which arise before the practical microscopist in the 
study of cancer, I have found it necessary to supply 
the want for myself from the abundant material which 
has come under my observation; and I have come 5 
to look upon the method which I have endeavored 
to bring forward in this paper, as one method, at 
least, if not the best method, for determining the qual- 
ity of malignant growths. 
Few studies tend to show the incompleteness of 
human knowledge more than that of pathology. Our 
entire stock of knowledge consists of a few simple 
facts, the result of observation and experience. Un- 
fortunately, the great truths of pathology are sur- 
rounded by so much of theory, that it is difficult at 
first sight to distinguish the facts from the theories; 
and the benefit to be derived from the substantial 
fact is frequently lost. When a theory is put for- 
ward, there necessarily comes in to make up the 
thread a great deal which is not realty truth, but 
which looks so much like it that when loosely stated 
it serves the purpose of supporting the theory based 
upon a few facts. And in this, I think, we find the 
reason why all theories pass away with the appear- 
ance of the new truths which are being constantly 
developed by the army of observers. Most of the 
theories of cell growth and decay are based upon 
the same facts; and their apparent difference, as 
stated by different observers, is to be found in the 
positive manner and detailed and exact method of 
stating them. Almost any theory which is based 
upon a real fact will hold good until its advocates 
push the arguments necessary to sustain the theory 
so far as to expose the real and usually small amount 6 
of truth upon which it is based; and then there is a 
change of doctrine, and another set of arguments, 
and a different direction is given to the same truth; 
and we find ourselves supporting an entirely differ- 
ent and sometimes opposite theory, with the same 
little truth as its groundwork. Thus, with a few 
facts and several theories, we may be able to per- 
suade ourselves that we are possessed of great knowl- 
edge, when, in fact, our knowledge extends no further 
than the simple fact upon which the theory is based. 
I feel that I am in this position in regard to the 
theory of cancer. The known truth of this disease 
is so small that it admits of many theories, and medi- 
cal men have not been wanting to spin them; so 
that there is but little chance for me to propound a 
new one, without the risk of doing injustice to the 
material used as a basis for this paper, which I 
would rather have appear as a practical contribution. 
Nevertheless, I find I cannot get through with my 
subject without the aid of some kind of theory; and 
the doctrine which accords best with the facts of my 
experience is a combination of the cell doctrine and 
the exudation doctrine. 
The molecular theory seems to me to be so far 
out of the reach of our present methods of examina- 
tion that it is next to impossible to demonstrate what 
little truth there may be in it. The practical appli- 
cation of this theory is as yet certainly out of the 
question. 7 
It is probable that there are two methods for the 
development of morbid growths ;—that of exudation, 
and that of continuous development from pre-existing 
cellular elements. At all events, these two doctrines 
will doubtless have each their advocates, from the 
fact that there is some proof for the existence of 
each. 
The truth will be found to be nearest approached 
by accepting the two modes of new formation, or two 
theories:—the continuous cell development, and the 
exudation theory, in combination. 
As nature has provided two ways for the healing 
of wounds (the union by “ first intention—a kind of 
continuous cell development; and union by granula- 
tion—a kind of cell development by exudation), so 
we find she has two ways of producing new formations. 
That we can demonstrate the exudation of plastic 
lymph in some situations, and a subsequent organiza- 
tion of the same, need not hinder us from believing 
that we may also find in other situations organization 
produced by direct cell development, without the 
interposition of an exudation. 
The first method we see illustrated in the exudation, 
on the pleura, and some serous and mucous tissues. 
Here the irritated tissues, blood-vessels, etc., through 
the instrumentality of cell action, pour out a liquid, 
which is used as a basis, afterwards, for the develop- 
ment of cells, which are a continuous development 
from the pre-existing cells in the surrounding part. 8 
In a similar way we find a clot becoming organized, 
as it is called, by the surrounding cells of connective 
tissue, or of the blood vessels using this fibrinous 
element of the blood as a convenient substance for 
the development of cell growth—set about by irrita- 
tion in the part. 
This is one of Nature’s restorative methods, and is 
a process of nature to repair either an injury already 
done to a part (wounds, etc.), or to protect a part 
from an injury about to occur (such as the effusions, 
etc.). 
Although the exudation theory and the cell 
doctrine appear to differ greatly, yet, I think, on close 
examination, they prove to be the same process of 
cell development, with, in the case of exudation, an 
additional element in the material used by nature for 
the transformation. This second process of develop- 
ment is unconnected with inflammation, and is the 
process by which tubercle, cancer, etc., are formed- 
According to this view, every cell must come from 
a pre-existing cell: there is no such thing as sponta- 
neous generation. The exudation is the pabulum 
for cell development; but it is prepared by the pre- 
existing cells in the part or around it. As the bird 
prepares her nest for the egg and young bird, so the 
animal cell prepares a nest or pabulum for the 
development and growth of its own kind. 
However much of truth there may be in the exu- 
dation theory, one thing concerning it is plain, viz.; its application to the study of morbid growths is very 
limited; for, the only means by which we can hope 
to recognize a difference in the various kinds of 
exudation are such as are of a chemical nature ; they 
are tedious- and unsatisfactory; and, after all, the 
advocates of the exudation theory themselves resort 
to the use of cells for their illustrations. 
There seems to be little hope, then, of recognizing 
any very definite and satisfactory characters in the 
exudations by our present mode of examination; and 
the cell is, after all, the ultimate element by which 
we must determine the character of morbid growths. 
The object, then, of all microscopic examinations 
of tumors is, to discover the peculiar kind of cells 
which compose the specimen under examination. 
This is readily done; and the profession has already 
a great accumulation of material of this kind. Cer- 
tainly, observations of this character have been 
made in sufficient numbers to establish thoroughly 
the peculiar varieties of cellular growths. This being 
done, the only question which remains is :—Have 
we a specific cancer cell, and is it diagnostic ? Can 
we determine with certainty that one tumor is can- 
cerous and another benign in its nature, by the 
character of its cells ? 
This question has not been satisfactorily answered 
to the minds of most physicians. There is a larger 
number who doubt the existence of a specific cell, 
which is necessarily present in all cases of cancer, 10 
than there is of those who believe in its existence. 
For my own part, I am willing to count my. 
self among those who have a positive and firm 
conviction of the existence of certain cells, which, 
when found in morbid growths, are diagnostic of 
cancer. 
I think we have two such cells. One is the 
“ mother cell,” or “ compound cancer cell,” long 
recognized by authors as the “ cancer cell.” It is, 
no doubt, peculiar to cancer; and when we see this 
cell, there is no longer any doubt that the specimen 
under consideration is a cancer. 
This is easy enough; but then we have tumors 
which do not present the mother cell, and yet go on 
to a fatal termination; and the microscopist may 
have great difficulty in placing the tumor in its proper 
category. Again, a tumor which at first does not 
present the mother cell may, in a short time, furnish 
plenty of them; and, besides, I think that no cancer 
in its early period presents the mother cell to any 
considerable extent, and perhaps not at all. 
If we are to render the best service to the patient 
attacked with this disease, we must know early in 
the case what we have to deal with; for this would 
influence to a great extent the treatment of a tumor. 
This cannot be told in the majority of cases, if we 
rely only upon the presence of the “ compound 
cancer cell.” 
If this be so, what else, then, is there to aid us in 11 
the diagnosis. I think that what have been called 
“ free nuclei ” by authors, in their descriptions of 
cancer, are the elements upon which we can rely 
with great certainty, and are in reality as specific 
cancer cells as the mother cell. I believe this is no 
nucleus, but a complete cell; and, using the number 
and arrangement of these cells in a given tumor as 
a basis for reasoning, I would have no hesitation in 
pronouncing upon its malignity, as well as the inhe- 
rent tendency there might be in the growth to affect 
other parts, or to return after excision. 
The peculiar cell to which I refer is found, to a 
greater or less extent, in all cancers; and in the 
early as well as in the later stages of their develop- 
ment. 
It has for its parent type the connective tissue cor- 
puscle—the embryoplastic cell. It is, doubtless, 
from this physiological type that all the other cells 
which compose the body have their origin. It is 
sparsely scattered about in the tissues of the adult, 
but it is found in great abundance in the fcetus. 
Indeed, it is best studied in the early development 
of the embryo, where, quickly changing its form, it 
passes readily into the fusiform caudate, epithelial 
or fibre cell, etc. 
It was after a careful study of these cells and their 
development in the embryo, that the doctrine of het- 
erology was found to be untenable, as it related to 
the division of tumors. 12 
I believe that most pathologists have abandoned 
the use of the term Heterologous, as it was first used 
to indicate malignity ; and it is now generally restric- 
ted in its use to indicate only the abnormal manner in 
which tumors sometimes arise, viz : such a growth as 
is at variance with the typical formation of the body. 
It is thought that by a careful search into the early 
elements of the tissues, a physiologtcal type has been 
found for every pathological formation. 
Heterology now means an error in the arrange- 
ments of the elements composing a tumor as to 
place or situation. 
Homology means air error as regards the quantity 
of elements in the structure—an hypertrophy. 
I desire to use these terms as thus defined—and 
to add to them another signification, which I hope 
to make plain as I proceed. 
The microscope reveals the earliest form of the 
embryo as a mass of homogeneous (homologous) 
cells. The form of the cell is similar to that of the 
connective tissue corpuscle, or embryoplastic cell. 
From this type it seems that all the other forms of 
cells and tissues found in the adult body arise. At 
certain periods in the growth of the embryo, we find 
marked changes taking place in the form of the cells ; 
and, instead of the simple embryoplastic cell, we find 
elongated cells, fibres and tubes—indeed a heteroge- 
neous (heterologous) mass. And just in proportion 
to the growth of the foetus do we find this heteroge- neity of cells, showing that normal development is 
dependent upon changes in the cells from a homoge- 
neous to a heterogeous collection. 
At one time tumors were divided into heterologous 
and homologous growths the idea of malignity being 
attached to heterologous ones and a benign charac- 
ter attributed to the homologous growths. 
These terms are good to retain, but their applica- 
tion, as it was formerly understood, must be changed • 
for what were supposed to be heterologous growths 
are in reality not so, if considered in the relation of 
the growth—as a tissue—to the other tissues of the 
body; and if we restrict the use of the word heterol- 
ogous to the growth itself, or rather to the tissue 
from which it has sprung, we then find that the can- 
cer cell is not heterologous but homologous-*-that is to 
say, the tendency of cell development in a cancer is 
to reproduce cells all of one kind and in a cancer, we 
find with the microscope that those tumors are 
the most malignant which are composed of a large 
number of cells of the same kind, each cell reproduc- 
ing its own kind, and having no tendency to take part 
in the support and normal growth of the tissue in 
which they are found. They have no natural limita- 
tion—influencing the cells in the neighboring parts to 
follow in the morbid process and in the tendency 
which they have to reproduce cells of a like kind with 
themselves; and if it were possible for the patient to 
live long enough, and the process to continue, the 14 
whole structure of the body would become in the 
end one mass of homologous cells. 
That is to say, it would be structureless, in the 
usual sense of the word; it would lack that variety 
of cell development which creates the plasma, the 
cell, and the fibre—this constituting a healthy 
tissue. 
Thus considered, normal tissue is heterologous, if 
looked at in reference to the cellular elements 
alone. 
The tendency of all normal tissue is to continue 
heterologous, and the moment that the tendency to 
heterologous formation flags, we begin to find cancers 
or homologous growths take their place. The malig- 
nity of a growth is in direct proportion to its homol- 
ogy- 
It appears, then, that all the normal tissues of the 
body have a heterologous structure. Nature seems 
to form perfect and staple structures upon this plan. 
Any deviation from this leads to unstable and short- 
lived structures. The more a tissue approaches ho- 
mogeneity in its structure, the more it tends to decay 
and death. The more of heterogeneity there is about 
a structure, the more stable is its condition, and more 
perfect its character and function. 
In the examination of a given tumor, to determine 
its character as to malignity, there are two questions 
to be answered by the microscope. 
ist. Is the specimen of tumor heterologous or ho- 15 
mologous, considered in its relations' to the original 
or parent type of the tissue in which it is located ? 
2d. Is the specimen of cell found npon microscopic 
examination heterologous or homologous, considered 
as regards the intimate structure of the tumor itself, 
in the relation of cell to cell; that is, do the cells in 
the specimen present any decided variety of form ? 
For example, do they tend to depart from their original 
cellular form and develop into fibre; or is there an 
arrest of the usual evolutions of cells which, under 
normal conditions, would form a definite tissue—a tis- 
sue which would be made up of a heterogeneous or 
heterologous mass of cells; for example, containing a 
due proportion of embryoplastic, fusiform, caudate 
and fibre cells ? or is it composed of a homogeneous 
or homologous mass of cells—cells which do not tend 
to develop into fibre, or present the usual development 
of the same variety of cell in normal tissue, but to 
form cell after cell of the same kind, never reaching 
any higher development than the embryoplastic form 
—in this sense a homologous cell growth ? 
The solution of the question of malignity is to be 
found in the answers which the microscope gives to 
these questions. 
A tumor may be heterologous as considered in its 
relations to itself as an individual structure, or 
heterologous in its relations to the other tissued of 
the body ; and in both cases be benign in its character 
But a tumor which is heterologous as to the other 16 
tissues, and homologous as to its own cells, is surely 
malignant. 
Again, a tumor which is homologous as to the other 
tissues and also homologous as to its own cells, is also 
malignant. 
But a growth which is homologous as to the other 
tissues of the body, and heterologous as to its own 
elements, is in almost all cases benign. 
These are the rules which may be applied to all 
kinds of tumors; and if the specimens for examina- 
tion are taken in the stage of actual development of 
the tumor, and before its retrograde metamorphosis, 
they will usually be sufficient to determine with great 
accuracy the quality and degree of malignity of 
morbid growths. 
The microscope has given us a convenient stop- 
ping place in the study of morbid growths, in the 
demonstration of their intimate and elementary 
structure, pointing out the fact that as a basis they 
are all composed of cells. 
Let us study, then, the character of these cells, and 
under what circumstances we find them ; their quality 
as regards malignity, and the tendency they have to 
return after extirpation; as well as their destructive 
tendency if left in the body. 
For the purposes of this paper, morbid growths 
may be divided into malignant, semi-malignant, and 
benign. 
A malignant growth is one which has an inherent 17 
tendency to destroy the tissues in which it may arise, 
and to reproduce similar growths in the different 
textures of the body (even after extirpation), causing 
cachexia, and, finally, death. 
A benign tumor is one whose injurious effects are 
entirely local, and the existence of which is usually 
compatible with good general health. 
A semi-malignant growth occupies a place between 
the other two classes ; commencing as a benign form, 
it subsequently assumes a malignant character. 
Inasmuch as it has been found that all growths— 
normal or abnormal—proceed from some kind of 
development of the connective tissue corpuscle—the 
embryoplastic cell—it naturally follows that when a 
previously normal growth (heterologous) becomes 
cancerous (homologous), it returns to the original 
type of its parent cell—the connective tissue cor- 
puscle. Therefore, we find the various forms of this 
cell as the chief elements of morbid growths. This 
cell seems to be the lowest and most elementary in 
the whole range of cells. 
When in cancers an effort is made at a higher 
grade of cell development, we find a cell is usually 
produced which is at variance with the parent type 
of the tissue in which it is found; for example, carti- 
lage or epithelial cells in the tissue of the uterus, etc 
From this fact, it has been supposed that great ir- 
regularity of form was one of the characteristics of 
cancer cells. This is not necessarily so; but it is 18 
usual to find in tumors which come between the 
class of pure encephaloid and scirrhus tumors, an 
admixture of cells; and these cells will present a 
great variety of form. They are apparently the last 
efforts of nature to maintain the original tissue as a 
heterologous structure. In this sense, then, the 
great variety of cells found in some cancers is an 
accidental characteristic, which may or may not be 
present, and should be valued accordingly. Doubt- 
less, industrious observers will hereafter find many 
varieties of such cells; but I think it matters very 
little whether they be cells having one spine or two 
spines—tails or ciliae—they belong all to this class 
of aborted cells. 
FORMS OF CANCER. 
The following are the varieties of cancer in the 
order of their malignity: 
1. Encephalgid Cancer. 
2. Scirrhus Cancer. 
3. Epithelioma. 
4. Enchondroma. 
It seems well to retain these standard names, 
although they do not perfectly express the kind of 
growth to which they are applied. 
They are associated readily, however, with the 
class of growth to which they belong, and are con- 
venient names on account of our familiarity with 
them. 19 
Almost all the varieties of pure cancer can be in- 
cluded in one or the other of these primary divis- 
ions. Their sub-divisions it is not deemed necessary 
to enter upon in the limits of this work. 
I shall now take up each of these forms of cancer 
separately, and apply to them the rules which I have 
proposed in the preceding pages, as follows : 
Encephaloid must be acknowledged as the type of 
cancer and malignity. 
ENCEPHALOID. 
It is here that the cancer cell may be studied best. 
In a pure encephaloid, one finds the two varieties 
of cancer cell in their perfection. Indeed, the en- 
cephaloid tumor is made up of these two varieties of 
cell. ,It is very rare that any other element is found 
to enter into its composition. 
Encephaloid, examined according to the rules al- 
ready laid down, presents the following varieties. It 
may be 
i st. Heterologous as to the other 
tissues, and homologous as to its 
own cells. 
Malignant. 
Again— 
2d. Homologous as to the other 
tissues, and homologous as to its 
own cells. 
Malignant. 
Encephaloid only occurs in these two forms. 
When a tumor passes these limits, it must be 
classed with one of the other forms of growth. 20 
SCIRRHUS. 
This comes next in order after encephaloid, and 
is subject to degenerate into encephaloid. It is a 
grade higher in the scale of pathological tissues as to 
structure. It has more of the fibrous element in it, 
and in the least malignant forms it has some ten- 
dency to heterogeneity of cell growth. It is found to 
vary greatly in the proportion of its constituent. 
Above it in the scale, we find the different forms of 
fibrous growths, and below it, the encephaloid. 
As to malignity, it may be arranged thus : 
I. 
Heterologous as to the other tis- 
sues, and homologous as to its own 
cells. 
Malignant. 
11. 
Heterologous as to the other 
tissues, and heterologous as to 
its own cells. 
Semi-Malig?iant; 
\ approaches fibrous 
tumor ; will prob- 
j ably become Ma- 
-1 lignant. 
Homologous as to the other 
tissues, and heterologous as to 
its own cells. 
111. 
A Fibrous Tumor, 
„ / 
Benign. Lan be re- 
* , . 
removed without 
, 
return. 
Homologous as to the other tis- 
sues, and homologous as to its own 
cells. 
IV. 
Malignant. 
EPITHELIOMA. 
The structure of an epithelioma is not composed 21 
always of epithelial cells throughout its entire extent 
and it is usually only towards the extreme surface 
that we find an abundance of well-formed epithelial 
cells. 
When an epithelioma is seated upon the skin, it 
usually extends itself by spreading to the surrounding 
surface and deeper parts, and is seldom found as a 
growth or tumor. A kind of ulceration follows this 
kind of cancer; and the true cancer cells, when they 
exist in an epithelioma, are to be found below the 
surface. Epithelioma remains benign so long as there 
is any heterology of structure as concerns the cellular 
elements; for example, presenting the connective 
tissue corpuscles, fusiform cells and epithelial cells 
together. As soon as the cells considered as parts 
of the tumor, as a whole (cell to cell), become homo- 
logous, then malignity begins. In this way an epithe- 
lial growth may become as thoroughly malignant as 
the worst form of encephaloid. Indeed, the entire 
face or a whole limb may be destroyed, bones and 
all, by this form of cancer. 
Epithelioma will be malignant or benign according 
as it is. 
Heterologous as to the other tis- 
sues and homologous as to its own 
cells. 
I. 
Malignant. 
11. 
Homologous as to the other tis- 
sues and heterologous as to its own 
cells. 
Benign. 22 
HI. 
Heterologous as to the other tis- 
sues and heterologous as to its own 
cells. 
Semi-Malignant, 
with tendency to 
become Malignant. 
Homologous as to the other tis- 
sues and homologous as to its own 
cells. 
IV. 
Malignant. 
ENCHONDROMA. 
Enchondroma presents the same qualities with 
regard to malignity as epithelioma. Indeed they are 
both most frequently benign in their nature. 
These and all the other sub-divisions of cancerous 
growths depend so much upon retrograde changes' 
(homologous changes), in the form of their cellular 
elements for the malignant type which they sometimes 
assume, that it is doubtful whether they ought to be 
classed with the encephaloid or scirrhus forms’ 
Myoma and osteoma, which come next in the scale 
are subject to the same degeneration, and might 
equally well be denominated cancer. A pure epithe- 
lioma or enchondroma cannot be malignant, so long 
as they sustain their structure perfect, as such 
Enchondroma belongs really to the semi-malignant 
group, and I have introduced it here more in illustra- 
tion of the views expressed in this paper than on 
account of any claims of its own. 
I therefore find it necessary to introduce a classifi- 
cation of the divisions and subdivisions of morbid 
growths, in keeping with the doctrines here set forth, in order to aid in their practical application. Here 
it may be asked, What is to be done with tubercle ? 
Is it not a homologous tissue considered as to its 
own cells? No! And here is just the explanation 
of the fact, that cancer and tubercle have always 
been separated by the pathologists. Examined in 
the early period of its growth, tubercle is really het- 
erologous as to its own cells, and homologous as 
to the other tissues. That is, it is developed in con- 
nective tissue from connective tissue corpuscles, and 
these cells pass on to a stage of development which 
is heterologous. It must be classed, then, with the 
benign growths. This may appear strange to some, 
but I think, on close examination, it will prove cor- 
rect. At all events it will not be likely to lead to any 
confusion, as tubercle is so readily recognized by the 
peculiar retrograde metamorphosis which its cells un- 
dergo. 
CLASSIFICATION OF THE SUBDIVISIONS OF MORBID 
Malignant 
i Encephaloid. 
I Scirrhus. 
GROWTHS. 
Semi-Malignant 
' Epithelioma. 
Myoma. 
Enchondroma. 
Benign 
Glandular tumors, etc., tubercle 
an(j some kinds of hypertrophy, 
etc. 
This classification is intended to represent well- 
defined forms of growth. They may all vary, how- 24 
ever, sooner or later in their course, and may even 
pass from one into the other. 
To be Malignant, a growth must be either homol- 
ogous as to the other tissues, and homologous as to 
its own cells; or, heterologous as to the other tissues, 
and homologous as to its own cells. 
A Semi-Malignant growth is heterologous as to 
the other tissues, and heterologous as to its own cells. 
A Benign growth is homologous as to the other 
tissues, and heterologous as to its own cells. 
I may here add that, to determine the character of 
a morbid growth or tumor by the aid of the micro- 
scope, the specimen of tissue used for examination 
must be taken from the part of the tumor which is 
either in its earlier stage of growth or at its height, 
and which is not undergoing any retrograde metamor 
phosis. The examination must be carefully made, 
and several portions from different parts of the same 
growth must be examined. The cancerous tissue 
must not be confounded with any of the remaining 
uormal structure of the part in which the growth may 
have lodged itself. 
When the two varieties of cancer cell exist in the 
same tumor, they are to be regarded as similar cells, 
and are not to interfere with the idea of homology; 
for they are in reality the same, in so far as one is 
capable of passing into the other, and neither have 
any tendency to further development—that is, to 
form fibre, etc. One is the “ simple cancer cell,” 25 
and the other the “ compound cancer cell.” The 
simple cancer cell is often found alone; but the com- 
pound cancer cell is never found without the simple 
cancer cell being also present. Strictly speaking, 
therefore, the simple cancer cell is, par excellence, 
the “ cancer cell.” 
PROGNOSIS. 
The prognosis of a given tumor will evidently 
depend upon the diagnosis as established by the 
plan laid down in the preceding pages. In fact, the 
prognosis is almost included in the diagnosis; for, 
if the growth be one of the four classes proposed, 
the process which has been gone over to place 
it in its proper category, and determine whether it is 
benign or malignant, has well nigh solved the ques- 
tion of prognosis. Still, this is to some extent vague, 
and it will be desirable to specify more particularly 
the individual species, and determine the prognosis 
for each. 
All tumors are subject to stages of growth, and 
have a certain course and history which belongs to» 
them as tissues. Thus, a tumor may be found at 
the time of examination in any of the following con- 
ditions : 
ist. Condition of Development. 
2d. State of Increase. 
3d. State of Resolution. 
4th. Condition of Abscess, Ulceration, Sloughing 
or Fatty Degeneration. 26 
5 th. It may be Stationary. 
These may be called the natural tendencies of 
tumors, when not interfered with by the surgeon. It 
will be seen that two of the conditions are processes 
of nature for getting the removal of the tumor ; and 
two are processes of development and increase. 
The fifth is a condition of inactivity. 
The first condition applies to all growths, and is 
simply the early stage. 
The second is the natural tendency of all tumors to 
grow, both by multiplication of their own cells, and 
by the involvement of surrounding parts. 
The third is a condition which is seldom met with 
in any of the morbid growths ; and in some, never. 
The fourth is sometimes a process of cure, and at 
other times of destruction, and rarely of propagation. 
The fifth is a condition to which all are liable, ex- 
cept encephaloid. 
Now, we can arrive at a tolerably definite con- 
clusion as to the prognosis in a given case, by finding 
out which of these conditions is the most likely to 
follow on in the natural order and tendency of the 
growth. Thus, it is plain that a tumor whose natural 
tendency is to resolve, or which has a history or 
record as a class to undergo resolution at times, and 
under certain favorable conditions would be entitled 
to a favorable prognosis, and those growths among 
which the process of resolution is seldom or never 
met with, would have an unfavorable prognosis; and 27 
the most unfavorable or fatal tumors would be those 
whose natural course included the xst, 2d and 4th con- 
ditions. In this way, we find that encephaloid- has 
a tendency to increase, and no inclination to 
and usually goes on to ulceration or sloughing; and 
when the diagnosis has been clearly made out as 
encephaloid, there is no chance for the patient with- 
out the most vigorous and heroic treatment; and, 
even then, he would be indeed a hopeful surgeon 
who would place any confidence in the safety of his 
patient. 
Scirrhus has a prognosis one degree towards favora- 
ble. It includes in its natural tendencies or conditions 
that of being (at times) stationary, and in this we may 
find a glimpse of encouragement, and the first step 
towards a favorable prognosis. lam confident, also, 
that there are cases of scirrhus which undergo resolu- 
tion. I remember a case of scirrhus of the breast 
which pursued such a course. 
Among the remaining kinds of growth some have 
an occasional tendency to spontaneous resolution 
(glandular growth, etc.); and others are susceptible 
of successful medical or surgical treatment under 
favorable circumstances. 
Thus we find that all cancers and cancerous growths 
have not the same prognosis, and that the hopeless 
character of a tumor increases as we approach the 
encephaloid variety. All other varieties are found, 
at times, in-conditions favorable enough to warrant 28 
an encouraging prognosis, if placed under judicious 
treatment and favorable circumstances. However, a 
favorable result is usually only possible under treat- 
ment ;. if left to themselves, they rarely take on the 
condition of resolution. A few casesfremain stationary 
for a long time, when left alone; but these cases are 
rare. The general prognosis in a case of cancer is, 
therefore, unfavorable. 
So much for the prognosis as it is usually con- 
sidered. But let us examine into the prognosis of 
morbid growths in another sense,—viz.:—What are 
the probabilities of a given tumor maintaining itself 
in its original or primary form ; for example, a fibrous 
growth remaining benign, or a scirrhus tumor sustain- 
ing itself as such, or, on the contrary, manifesting a 
tendency to pass into encephaloid ? And, again, 
what are the probabilities of a growth spreading to 
the surrounding healthy tissue ? or of its becoming 
circumscribed and stationary, and in this sense in- 
fluencing the general prognosis to be arrived at, if 
only the class of tumor, as a benign or malignant 
growth, be considered ? 
These questions, anticipating the direction in which 
a given growth is moving, or is likely to move, may 
be answered to a considerable extent by the examina- 
tion of the growth according to the rules which we 
have given for each class of tumors; and it appears 
to me that this will be a great aid in determining the 
course of treatment to be pursued; for if we can de- 29 
cide that a tumor has a tendency to remain stationary, 
we would perhaps be glad to let it alone; and if a 
scirrhus growth, or an epithelioma, showed a ten- 
tency to progress rapidly in the direction of malignity, 
the knife or other heroic treatment might be justified. 
I am satisfied that in a general way we may decide 
these questions. At all events, any light in this 
direction will not be unacceptable. I, therefore, refer 
to this point to indicate that the rules here set forth, 
while bearing upon the general prognosis, may also 
show, in most cases, the special tendency of a growth 
at the time of examination ; thus giving a special prog- 
nosis, and one which would determine to a great ex- 
tent the treatment appropriate for each case. 
In forming the prognosis, then, two considerations 
are to be taken into account : 
ist. The solution of the question of malignity. 
2d. Whether the growth is capable of sustaining 
itself in its primary form. 
This last point, of course, refers chiefly to the 
semi-malignant or benign forms. When applied to 
malignant forms, it would involve the question of 
the reproduction and return of tumors. 
As these points may all be decided at the time of 
making up the diagnosis, and by the same rules, I 
wish here only to refer to them, and point out their 
extended application in this manner, as well as allude 
to their use in indicating the direction in which to 
look for a successful treatment. To sum up, then, 30 
the prognosis for the different kinds of growths, we 
find encephaloid occurring in only two forms. It is 
either found as a growth which is 
i st. Heterologous as to the other tissues, and 
homologous as to its own cells; or, 
ENCEPHALOID. 
2d. As one which is homologous as to the other 
tissues, and homologous as to its own cells. 
The prognosis in both cases would be unfavorable. 
If any difference pould be made, it would be, of 
course, in favor of the second form. 
SCIRRHUS. 
Scirrhus has a larger range, and includes four 
qualities of structure. Thus we find it: 
Ist Division.—Heterologous as to the other tissues, 
and homologous as to its own cells. 
In this form it is thoroughly malignant, and should 
have a prognosis quite as severe as a pure encepha" 
loid. 
2d Division.—Heterologous as to the other tissues, 
and heterologous as to its own cells. 
This is an example of the semi-malignant class. It 
approaches the fibrous tumor, and will have a ten- 
dency to become malignant or to remain stationary, 
according as its cells show a tendency to form, in the 
first case, a homologous collection; or, in the second 
case, a heterologous collection. The prognosis for 
this variety is also unfavorable ; still, it includes some 
ground of hope, either from treatment or operation, 31 
3d Division.—Homologous as to the other tissues, 
and heterologous as to its own cells. 
This arrangement of cells forms a simple fibrous 
tumor, which would have a very favorable prognosis. 
It is possible for such a tumor to remain stationary 
for a long time, and it may be extirpated with but 
little or no chance of a return. It is one of the forms 
of benign growth, and is given this place on account 
of its occasional malignant tendency. 
4th Division.—Homologous as to the other tissues, 
and homologous as to its own cells. 
This, like the first form, bears the characters of 
malignity in a marked degree, and is entitled to a 
corresponding prognosis. 
In order to correctly determine the prognosis of 
an epithelioma, it is necessary to understand that all 
growths which come under this denomination do not 
present the same qualities as to malignity; and to 
recognize, also, that these growths may vary from a 
simple and harmless epithelial growth to the most 
severe cancer. The cells which are found in these 
tumors will also vary greatly, and may be chiefly 
epithelial or only in part such; and we may find at 
times cells which resemble in no respect the epithelial 
cell. A predominence of the epithelial form of cell, 
however, is usually a characteristic of epithelioma. 
EPITHELIOMA. 
This form of growth is subject to the same possible 
variety of cell development, and to the same changes 32 
in the quality and form of its cells, as scirrhus; 
and may be divided, like it, for the purpose of deter- 
mining the prognosis, into four kinds, viz.: 
ist Division.—Heterologous as to the other tis- 
sues, and homologous as to its own cells. 
In which case it would be malignant, and must be 
given the same prognosis as the first forms of scir- 
rhus and encephaloid. Such a growth will most cer- 
tainly be reproduced or return after operation ; un- 
less, perhaps, the excision be performed very early, 
and followed by appropriate treatment. 
2d Division.—Homologous as to the other tis- 
sues, and heterologous as to its own cells. 
This would form a benign epithelioma, and may be 
treated or operated upon with confidence, in the 
probabilities of no return. 
3d Division.—Heterologous as to the other tissues, 
and heterologous as to its own cells. 
This has a semi-malignant character, and should 
have a prognosis according as its cells showed a tend- 
ency to sustain themselves as a heterologous collec- 
tion, or the contrary. 
4th Division.—Homologous as to the other 
tissues, and homologous as to its own cells. 
This form possesses the same malignant character 
as the first division; but it has a more favorable prog- 
nosis, inasmuch as there is some tendency in it, at 
times, to remain stationary. 
In connection with epithelioma, and before passing to the consideration of enchondroma, it will be well 
to state (what in fact has been admitted all through 
this paper) that it is not absolutely necessary for 
either the compound cancer cell or the simple cancer 
cell to be present, in order that the growth may 
partake of a malignant character. A collection of 
epithelial cells, or cartilage cells, etc., may be arranged 
as a heterologous-homologous or homologous homo- 
logous collection, and impress the growth with a cor- 
responding character—a character which might be de- 
rived from such an arrangement of any variety of cells, 
and which would indicate more a tendency to pass on 
from a semi-malignant to a malignant form, than they 
would an already existing malignant form. When an 
epithelioma becomes malignant, there, is always found 
among the epithelial cells one or the other of the 
forms of cancer cells. And upon the number and 
arrangement of the cancer cell present we may decide 
the prognosis. 
ENCHONDROMA. 
The enchondroma belongs, as has already been 
shown, to the same class as the myoma and osteoma. 
These are all, properly speaking, semi-malignant, and 
as such are, of course, subject to a more favorable 
general prognosis. The special prognosis is to be 
determined by deciding (according to the rules given 
for scirrhus and epithelioma) whether the growth is 
capable of sustaining itself in its primary form; or 
whether it is passing on to the thoroughly malignant 
type. 34 
For a description of the general characters of 
malignant disease, we must refer to more extended 
works on the subject. It is not in keeping with the 
limits prescribed for this paper to review the history 
of cancer, or to determine how ancient a disease it 
may be, or how faithfully its strange features have 
been portrayed to us by authors. 
There are, however, a few points concerning the 
disease which are entitled to a special notice on 
account of their importance, and for the reason that 
all observers do not agree concerning them. As 
they have been adopted in this paper as facts, some 
explanation seems necessary to their proper under- 
standing. For convenience they may be divided 
into six propositions, as follows : 
Propositionist.—Cancers arise, as a rule, directly 
from tissues which were onde healthy and normal. 
This proposition seems self-evident, unless we 
admit the doctrine of spontaneous generation, or the 
exclusive exudation theory and it need not detain 
us further than to refer for its demonstration to the 
case of cancer of the omentum (reported in another 
part of this paper), which illustrates well the produc- 
tion of cancer from normal cells. This was a clear 
case of cancer, developing in connective tissue from 
connective tissue cells. 
The omentum, having no other cells from which the 
growth could spring, and the whole of the omentum 
being occupied by the disease, it is fair to suppose 35 
that it must have once presented its normal cells in 
some part, at least, of its extent. That it does not 
now present in any part the normal connective tissue 
cell, seems to me proof that these cells have de- 
generated into cancer cells; and we are forced to 
believe that the normal tissues have been converted 
into this abnormal structure. 
Proposition 20.—A benign tumor may assume 
a malignant character, and become in the end true 
cancer. 
The truth of this proposition is not so clear to 
most physicians; yet, admitting the first, this natu- 
rally follows. It seems less improbable that a 
growth which is originally benign may take on a 
malignant course, than that a cancer should be found 
developed from a healthy tissue in the first instance. 
The doctrine is confirmed by every-day experience; 
for example, semi-malignant growths. 
Proposition 30.—All morbid growths are en- 
dowed with the power of reproduction to a greater 
or less extent; and it is this power which determines 
and limits the degree of malignity of a tumor. 
Such a property is accorded by all to cancers; 
but probably few will be willing to admit that what 
are known as benign tumors, are possessed of the 
power of reproduction. Nevertheless, the adoption 
of the two preceding propositions forces the ac- 
knowledgement of this one. It is not pretended 
here, however, that benign growths possess the 36 
power of reproduction in any other than a latent 
state; otherwise, they would be removed at once 
from the benign category; but that there is a latent 
power of reproduction in benign growths is demon- 
strated by the facts observed by every surgeon. 
How often does it occur that a tumor, which has for 
a long time presented a benign history, suddenly, 
from the effect of some irritation, such as a surgical 
operation or an injury, takes on a malignant course, 
or develops the power of reproduction ? The simple 
effect of operation or injury is certainly insufficient 
cause for the production of a malignant quality, 
unless there had already existed in the tumor an in- 
herent or latent power, which only needed such a 
stimulus for its development. This doctrine is 
further supported by the general principles of cell 
development, and it is, besides, necessary that it 
should be adopted in order to take a comprehensive 
view of morbid growths, and to enable us to distin- 
guish and separate the benign from the malignant. 
All cancers are not reproduced with the same 
rapidity, or with the same ease or frequency; and 
because we can trace the diminution of this power 
in growth, further and further, until we come 
to a growth which rarely manifests any such power, 
and we call this a benign growth, are we cer- 
tain that this is, any more than an apparent 
limit ? I think not ; and if, occasionally, benign 
growths are known to take on a malignant 
action, I believe it is sufficient to warrant us 37 
in concluding that they also possess the power of 
reproduction, and that in them it is latent. So long 
as this power is not aroused by irritation or certain 
external circumstances, the tumor will remain benign. 
Why is it that one kind of cancer is more easily 
reproduced than another ? 
An answer to this question can only be given by a 
study of the facts observed in the development of 
morbid growths. 
It seems probable that one growth is more easily 
reproduced than another, according as it has its ori- 
gin in the connective tissue corpuscles, or in the 
higher grades of cells. 
Encephaloid is the most certainly and easily repro- 
duced, because it originates in the connective tissue 
corpuscle, and because the original vice which causes 
such tumors is deeper seated and more thoroughly 
constitutional. 
In encephaloid, the disease runs its course in one 
grade of cells ; it has no changes of form to make ; 
the malignant course once begun, it is easily contin- 
ued. Nature uses the connective tissue corpuscle 
freely for a>ll the repairs of structure; it is the tumor 
tissue, the scar tissue, and well called the connective 
tissue. Of all the cells of the body this is the most 
easily produced and reproduced. It is also the most 
convertible of all cells. It depends for its support 
directly upon the blood, and is therefore more readily- 
affected by any constitutional vice. 38 
The higher grades of cells which compose cancers 
are dependent for their support upon the surrounding 
cells, and are more local in their dependencies than 
cells of the lower grades or types forming cancers. 
These higher grades of cells, receiving their support 
more indirectly, depend less upon the constitutional 
taint. 
Nature uses these cells for the structure of organs 
required for the functions of secretion, excretion or 
activity; they are more difficult to reproduce even 
normally, for we find the solution of continuity of any 
of these organs repaired by the connective tissue 
corpuscle, and it is only by reason of the peculiar 
convertible properties of the connective tissue cell, 
that the secreting or excreting cell, as the case may 
be, finally results. 
These ceils, coming originally from the embryoplas- 
tic cell, are more likely to return to this type when 
they undergo a retrograde development, or cancer- 
ous degeneration. 
Indeed, it is necessary that they should return 
more or less to this form, before they can assume 
a thoroughly malignant type, thus requiring a double 
effort. They are, consequently, more difficult to re- 
produce after excision, because the abnormal cell 
which at first had undergone the retrograde change 
and become the starting point of a malignant devel- 
opment, being removed, some other cells have to suc- 
cumb to the constitutional or cancerous vice, before 39 
the process can continue; and thus a longer or 
shorter period of time must intervene between the 
removal and the reproduction of a growth. The 
length of time required depends upon the kind of 
cell, originally the seat of the disease; whether it 
is easily changed; and whether it assumes readily the 
form and function of the cells in question. If it 
does, there will be a short period ; if it does not, 
then there will be a long period intervene. If the 
tumor be composed of cells which are of a very high 
grade of the scale, it will be reproduced with great 
difficulty, and under favorable circumstances not at 
all. 
Proposition qxn.—A cancer once begun, either 
continues on in its original form, as an encephaloid, 
scirrhus, etc., as the case may be, or else it assumes 
the encephaloid form ; each form of cancer repro- 
ducing either its own kind, or else the encephaloid. 
The possible exception to this rule is found in the 
encephaloid, which, as we would naturally suppose, 
may assume any of the other forms, having as it does 
the embryoplastic cell for its basis. The transition 
from the encephaloid to the scirrhus seems but a 
step ; still, as this would be a step in the benign direc- 
tion, it is probable that it rarely or never occurs. 
Proposition STH.—Any of the forms of cancer 
may reproduce the encephaloid instead of the original 
form. This change of form frequently occures, and 
the knowledge of it explains to us why it is that a 40 
growth such as an epithelioma or scirrhus, which, 
might have been pursuing a semi-malignant course, 
and promised well to be successfully removed by 
operation, after the removal not only returns, but 
returns with much greater malignity, and runs its 
course rapidly and fatally. Such cases will be found, 
on examination, to have changed their original form 
for the encephaloid. The growth which was progres- 
sing slowly and with difficulty, with a high grade of 
cells as a basis, on the event of removal, finds it im- 
possible to reproduce the same grade of cell, and 
at once takes hold of the connective tissue corpuscle 
as an easy prey, and the case terminates in an ex- 
plosion of malignity. In most cases, however, the 
general rule holds good, and we usually find cancers 
reproducing their own kind. 
Proposition 6th. -The Convertibility of Cells. 
—ln order to interpret correctly the various pathologi- 
cal formations known as tumors, and especially that 
of cancer, we must recognize certain possible trans- 
formations of which the cells of any of the 
physiological as well as pathological, are capable— 
transformations upon which, indeed, in one sense, 
the development and growth of the tissues depend- 
This feature of cell growth may be conveniently 
called the convertibility of cells. 
The study of the minute elements of the tissues 
of the body shows us that they are each composed 
of definite cellular elements, but that the cellular ele- 41 
merits which are to be found composing an organ or 
a tissue in its perfect or mature form are not always 
the same, in appearance at least, as those found 
during its formative state. In some instances—as for 
example, in muscle, nerve, etc.—the difference be- 
tween the appearance of the cells found in the ex- 
amination of a tissue during its formative or embry- 
onic state, and that found when it is fully developed, 
is so great that it would be possible to recognize them 
as the same only by following them in the different 
stages of development. 
By taking each of the tissues and tracing these 
changes backwards, we find their ultimate form to be 
the embryoplastic cell. This cell may be changed into 
any of the other varieties of cell, and they in their 
may be reconverted into the embryoplastic cell. 
Thus we find a progressive change of cell formation, 
and a retrograde change of cell formation. Under 
the head of progressive change of cell formation, 
may be included the normal growth of tissues, the 
various simple hypertrophies, and some adventitious 
growths. 
The retrograde changes of cell formation include 
the various morbid growths, cancers, tubercle and 
some hypertrophies, etc. Were it not for this conver- 
tibility of cells, the renewal, the waste and repair of 
tissues, and especially the development of morbid 
growths, would be impossible. 
I think we find, in the doctrine of the convertibil- 42 
ity of cells, a clue to a better understanding of the 
order in which we find morbid growths are devel- 
oped and reproduced; for, the order of convertibil- 
ity of the different cells is in keeping with the facts 
of development and malignity. 
It explains also, how each diathesis may produce 
from a single form of cell, a growth peculiar to itself. 
The cancerous diathesis in developing locally pro- 
duces cancerous tumors, by its influence upon this 
convertibility of cells. The tubercular diathesis uses 
the same cell for its development. Thus, from the 
same elementary cell, as a basis, we may have any 
of the varieties of tumors produced. 
The embryoplastic cell comes first in the order of 
convertibility, and it is also first in malignity. The 
other forms being less convertible, and also less ma- 
lignant. 
The following table presents order of the con- 
vertibility of cells in their physiological and patholo- 
gical development; showing the relations of the 
degree of convertibility of cells, to the degree of ma- 
lignity of tumors. In the first column we find a phy- 
siological cell development, in the second a patholo- 
gical cell development:— Order of Convertibility 
of Cells. 
Order of Malignity of 
Tumors. 
Physiological. 
Pathological. 
Form of Cell. 
Form of Tumor. 
Embryoplastic cells. 
Fusiform, caudate and 
fibre cells. 
Epithelial cell. 
Cartilage cell. 
Muscle cell. 
Cone cell. 
Nerve cell. 
Encephaloid tumor. 
Scirrhus. 
Epithelioma. 
Enchondroma. 
Myoma. 
Osteoma. 
Neuroma. 
The influence of a normal vital force acting upon 
the embryoplastic cell, converts it into its appropriate 
form for the tissue or organ for whose function it is 
required. The form of the cell is maintained only 
as long as the vital force is exerted normally upon it. 
As soon as this force is withheld or is exerted under 
abnormal influences (the various diatheses, etc.), the 
convertibility of the cells permits of the formation of, 
tumors and cancers. 
In virtue of this universal convertibility of cells, we 
find that a tumor may originate in any tissue, and i 
may partake of the cellular form of the elements of 
that tissue, or it may assume an entirely different 
form. And a tumor having commenced in one form, 
it may be converted into, and continued in, another 
form. 44 
In normal processes it is necessary for the integrity 
of a tissue that its cellular elements should retain 
their typical form, or pass on in regular and succes- 
sive stages to their final limits. The convertible 
properties of’the cells are thus kept in their legitimate 
channel. In pathological processes concerned in 
the formation of tumors, this convertibility of cells 
is subject to the controlling influence of the pre- 
dominating diathesis, and pursues an irregular course, 
following, to a certain extent, the physiological order, 
and developing a simple or benign tumor, and some- 
times skipping several of the steps in this order, and 
forming tumors whose cellular elements are at 
variance with the form of cell found in the original 
tissue; at other times descending from a perfectly 
developed cell formation to the embryoplastic form, 
and producing cancers. 
CAUSES OF CANCER. 
In cancer, as in all other diseases, we must admit 
the existence of a positive and definite cause, acting, 
when under the same circumstances, always in the 
same way. A subtle and unknowable influence, 
which produces out of the once healthy tissues the 
abnormal products which we know as malignant 
growths. These growths are the results of the 
operation of a pathological law, which has its exist- 
ence as well while the tissues are normal as when 
they become diseased. The law, however, is not 45 
always in visible operation; but, like the other laws 
of nature, is usually set in operation by secondary 
causes. It would be useless for us to seek to know 
this prime cause or essence of morbid growths; but 
it is probably akin to the laws of attraction and 
gravitation. 
The secondary causes, or those which operate in 
setting in motion this prime cause or pathological 
law, are proper subjects for our investigation and 
study. These causes we may observe and under- 
stand to a certain degree ; a perfect knowledge of 
them would be a substantial basis upon which to 
found a successful treatment for the cure of these 
diseases, and it would also enable us to prevent 
them. 
Looked upon in this light, the causes of cancer 
are numerous, and may be divided into external and 
internal causes. 
The external causes of cancer are those which 
operate locally, such as injuries or local irritations, 
impressions made upon the tissues by forces acting 
from without. 
The internal causes are those which are dependent 
upon forces within; the individual, for example, a 
constitutional vice, or a hereditary taint. 
For our present purpose, the combined causes of 
cancer may be enumerated thus : 
i st. Heredity as a cause. 
2d. The blood as a cause. 46 
3d. The nervous system as a cause. 
4th. Injury as a cause. 
sth. Accidental errors of cell development, fol- 
lowed by a kind of contagion by cell contact. 
6th. A retrograde tendency of cell growth, in 
which the whole system and all the tissues partake} 
and which is manifested locally in the form of can. 
cerous tumors, and constitutionally in the form of 
cachexia. 
HEREDITY AS A CAUSE. 
The confidence which the professional mind has 
reposed in the fallacious arguments of statistics has 
done much to place the professsion in the humiliating 
position where it is found at present concerning the 
heredity of cancer—of at one time advocating as an 
established fact a doctrine which afterwards they 
protest against, upon the same grounds of proof as 
those upon which they at first advocated it. They go 
from one extreme to the other—having once taught 
that cancer was hereditary in most cases, they now 
teach that it is scarcely ever hereditary, and we are 
even asked to believe this statement on the ground 
that statistics prove it. Let us beware of statistics, 
having misled us once, they will probably do so again; 
There is probably more value in individual impres- 
sions, gathered from a large and well considered 
of observation or experience, summed up and 
divested of all prejudice, than can be found in a 
volume of statistics. 47 
It is in this liberal manner that I propose to consider 
the causes of cancer, leaving the proofs of statistics 
for those who have more confidence in them than I 
have, and believing myself that, until we adopt a 
uniform method of diagnosis, no reliable data can be 
obtained from statistics. 
We are, therefore, left, for the proof of the heredi. 
tary nature of cancer, to reasoning, analogy and 
experience. 
WHAT IS HEREDITY. 
Those peculiarities which belong to the individual 
as a member of the human family can hardly be said 
to be heredity, for we are all endowed with the traits 
of the race of mankind by the Creator from the 
beginning. One individual has not more to do with 
the transmission of these than another. 
The diseases which follow the natural degenera- 
tions of the body as age advances cannot be said to 
be hereditary in any proper sense. Health is not 
hereditary, and cannot be: it is an endowment of 
nature. 
Disease may be either acquired or hereditary. 
An acquired disease is one which attacks an indivi- 
dual on account of some personal fault or habit of 
body, or is due to accidental influences. 
Some acquired diseases make such an profound 
impression upon the individual, through the blood or 
the nervous system, or both, that they are identified 
with it, and are, or may be, transmitted to the offspring 48 
of the individual, without the offspring ever being 
subjected to the influences which caused the disease 
in the parent in the first instance. Such a disease is 
said to be hereditary. 
A hereditary disease, then, is one which is capable 
of leaving such an impress upon the blood or the 
nervous system of the individual first acquiring it, 
that it becomes one of the controlling forces of the 
economy, and is inherited by the offspring in the same 
way as the normal or vital controlling forces of the 
body are transmitted. 
We do not want for examples of such hereditary 
diseases; we find them in syphilis, scrofula, tubercle, 
rheumatism, gout, etc. If a disease is hereditary, it 
must be so either on account of some constitutional 
poison or virus introduced into the blood or the system, 
and which has a specific effect, according to its kind, 
or else it is hereditary on account of some superin- 
duced peculiarity of structure or texture of the tis- 
sues which renders them more liable to be affected 
by certain causes than they otherwise would be. 
We have, therefore, two kinds of heredity: 
ist. Constitutional taints, such as that caused by 
the syphilitic or other virus. 
2d. Peculiarities of organization, and certain apti- 
tudes of constitution, such as tubercle, rheumatism, 
scrofula, etc. 
Having given this definition of heredity, and de- 
scribed some of its characters, we may now ask, is can-