THE HABIT OF GROWTH. 
AN INTRODUCTION TO A DISCUSSION UPON CARCINOMA AT THE MONT- 
REAL MEDICO-CHIRURGICAL SOCIETY, DECEMBER 13th, 1895. 
BY 
J. G. ADAMI, M.A., M.D., 
Professor of Pathology, McGill University ; Pathologist to the Royal Victoria 
Hospital. 
Reprinted from the Montreal Medical Jozirnal, February, 1896. THE HABIT OF GROWTH. 
AN INTRODUCTION TO A DISCUSSION UPON CARCINOMA AT THE MONT- 
TREAL MEDICO-CHIRURGICAL SOCIETY, DECEMBER 13TH, 1895. 
By J. George Adami, M.A., M.D. 
Professor of Pathology, McGill University ; Pathologist to the Royal Victoria 
Hospital. 
Frankly, gentlemen, it is impossible to do anything approaching to 
a discussion of the cause, progress and histological characters of can- 
cerous growths in the time allotted to each of this evening's speakers, 
and I am bound, therefore, to select one single aspect of the subject 
for treatment, and even then can at the most touch rather than 
treat it. 
Perhaps that which is of most general and present interest in con- 
nection with cancer, both from the point of the pure pathologist and 
from the standpoint also of the practical man, is the question of the 
causation of cancer. I say from the point of view of the man in 
practice, because once the cause of cancer is surely established it is 
generally held that prevention will be possible. This is the general 
hope, but for myself I am a little doubtful as to whether this really 
follows. I am not quite sure that when we establish satisfactorily 
the aetiology we shall find matters so simple that we can readily 
abolish or prevent the cause. Even if the condition be of a parasitic 
development, even if we are able to cultivate the parasite outside the 
body, and thus gain an intimate knowledge of its life history, I am 
not wholly hopeful that we can assume upon the analogy of modern 
bacteriological achievements and feel assured that eventually we can 
find means of arresting the growth of the parasite, and so of arresting 
the cancerous process, for, as I shall proceed to show, the modus 4 
operandi of the parasite must differ essentially from that of the 
micro-organisms of ordinary zymotic disease. At the present time the 
most that can honestly be said with regard to the results of the 
investigations into the parasitology of cancer is that those investiga- 
tions have revealed the occasional presence in the cancer cells of a series 
of very curious bodies. These bodies may be of the nature of sporozoa, 
they may with perhaps equal plausibility be regarded as the results 
of endogenous cell degeneration. So long ago as 1889-90 I gave out 
and demonstrated to my morbid histology class at Cambridge sections 
of a cancer of the scrotum showing these bodies. I am as much in 
doubt as to the nature of these bodies to-day as 1. was then. I leave 
it to Dr. Martin to bring before the Society the main results of the 
observations that have been made in this subject so far. 
But it seems to me that even if we grant that cancer is caused by 
this parasite, we have not arrived very much further. In the first 
place, in all other parasitic and microbic diseases with which we are 
acquainted, general infection is brought about by the conveyance of 
the microbe from the primary seat of growth to other regions of the 
body by the lymph or the blood stream. In cancer general infection 
(a term which in consequence I am inclined to dislike seeing used in 
this connection, I prefer " metastasis") is essentially associated with a 
totally different process, namely, the conveyance of tissue cells. It is 
the cells carried to other regions by the lymph or the blood stream that 
there proliferate, and the secondary growths are in the oldest and 
strictest sense colonial. Just as the old Greek colonies were estab- 
lished by members of a community who migrated to a distance and 
there founded a newT community of like constitution to the old, but 
wholly separate and owing no allegiance, so is it with the metastatic 
cancer growths. Even if in these migrating cells parasites be present, 
it must be admitted that we are dealing with a new type of infection 
wholly distinct from that induced by the tubercle bacillus, for 
example, and as a consequence we cannot predicate that the laws 
determining the prevention of one will determine the prevention of 
the other. 
In the second place, granting that parasites bear an setiological 
relation to cancer, we are still left in the dark as to why parasites 
induce certain cells of the body to take on a functionless and hetero- 
topic growth. At most we acknowledge that an obscure organism 
originates aberrant vital processes on the part of sundry cells ; and 
inasmuch as similar aberrant vital processes are known to take place 
in other cells without there being any suggestion of similar parasites 
being present, we are led, I think harmfully, to separate off sharply 5 
conditions which are related, we are led to neglect the attempt to find 
some common cause for all these conditions, we are led to separate 
sharply the malignant epithelial growths (I use this term in its 
broadest sense) from the malignant connective tissue growths; or 
if this be denied, and the sarcomata be accepted also as of parasitic 
causation, we are, at least, led to separate all malignant growths from 
all benign growths; we are conducted, that is, to an .impasse. For 
this may be definitely accepted that certain benign growths are 
wholly unassociated with the presence of any parasite. Take, for 
example, the little lamellar fibromata to be seen upon the capsule of 
the spleen, or take the papillomatous overgrowth of the mucosa at the 
edge of a chronic intestinal ulcer, take the long finger-like down growths 
of epithelium at the boundary of a chronic ulcer, or the bony over- 
growth upon the inner side of the femurs of cavalry soldiers. In all 
these cases chronic irritation is absolutely sufficient to explain the 
developments, yet no distinction can well be drawn between these 
chronic inflammatory hypertrophies and other forms of benign 
tumours. We must, then, logically admit that functionless and 
heterotopic cell hyperplasia can be induced without parasitic associa- 
tion ; and inasmuch as the benign may pass imperceptibly into malig- 
nant growths, and inasmuch as we can, for example, come across 
lipomata showing transition into sarcomata, or fibromyomata doing 
exactly the same, as again we can, in thyroid, encountor what are 
certainly benign growths-adenomata (the so-called foetal adenoma)- 
possessing all the histological characters of carcinomata, the only con- 
clusion to be reached is that a study of the presumed parasite is 
calculated to lead us only a very little distance. 
We must seek deeper than these suppositious parasites if we wish 
to discover what lies at the bottom of all malignant tumour growth, 
aye, of all functionless cell proliferation. 
Now, that I may prepare you for the train of reasoning upon which 
I am about to embark, and that you may throughout the ensuing 
argument see whither it is tending, let me here state the conclusion at 
which I have thus far arrived from a study of neoplasms and not a 
little consideration concerning their characters and relationships. 
Briefly, I cannot but hold that the one fundamental phe- 
nomen underlying the development of cancerous 
and other neoplasms is the assumption of a habit 
of growth, a habit of rapid cell division inde- 
pendent of external stimulus on the part of 
certain cells in one or other region of the body. 
The power of growth and multiplication is not, it must be borne in 
mind, something new to the cell. Every cell in the body, we may 6 
safely say, either possesses or has- possessed it. In every tissue, to 
the end of the life of that tissue, there is a constant, even if slow 
death of certain cells and replacement by cells of the same order, 
derived by proliferation of cells of that order. There is latent, that 
is to say, in all the living cells of the body a capacity for multiplica- 
tion requiring only the necessary stimulus to call it into play. The 
habit of growth to which I have referred above is an exaggeration, 
or more exactly, a calling into full activity of this latent capacity. 
This latent capacity for growth is much more intense in the vege- 
table kingdom, and numerous examples might be given in illustra- 
tion. I need only remind you that if you nip off a piece of a begonia 
leaf, and place it under favourable conditions, that piece will develop 
into a complete plant. The cells of this leaf, highly differentiated as 
it is, have the latent power of orderly proliferation to such an extent 
that they can reproduce the whole plant. 
Among the lower animals the same property is equally well 
marked. Cut a hydra into, I believe it may be said, almost as many 
parts as there are cells, and, provided that healthy and intact cells 
are left in the sections, each portion will develop into a complete 
hydra. The latent capacity for growth is such that each cell appears 
to have the potentiality not simply to produce cells of like order, but 
to reproduce the whole animal. 
Ascend higher in the scale, and the latent capacity becomes more 
limited. In the Crustacea for example, the potentiality is restrained 
to the reproduction of lost parts. Here the cells of various tissues 
proliferate harmoniously, and every tissue of the lost part is repro- 
dued in proper proportion. Ascend yet higher, and the latent 
capacity is yet further restricted ; so that in man we observe the 
following, namely, that only the cells of certain relatively simple 
tissues possess to any marked degree the power of complete reproduc- 
tion. 
It may be said that all this is trite and commonplace, and it may 
be asked what it has to do with the pathology of carcinoma. Well, 
the recapitulation is valuable to this extent that it helps to impress 
upon us the proliferative capacity of the cells of the body, and the 
limitations to that capacity in the higher animals. As a matter of 
fact, it is only in the higher animals in which these limitations have 
been impressed upon the cells that malignant growth is possible and 
is found. In lower animals any stimulus to cell proliferation leads to 
reproduction either of the whole individual or of a complex of tissues 
Recognising, then, the existence of this latent power of prolifera- 
tion on the part of cells with the limitations that I have mentioned, 7 
let me pass on forthwith to its bearing upon cancer formation, leaving 
aside, from lack of time, any consideration of the development of 
histoid tumours, even though I do this at the risk of being accused of 
passing by what is difficult to explain. 
While in man we observe, as I have above stated, that only certain 
of the simpler tissues exhibit any marked power of proliferation 
leading to complete reproduction, the latent capacity for growth is 
present all the same, and we notice the appearance of a further and 
allied phenomenon. We see that under suitable irritation the cells of 
these higher tissues have not lost entirely their capacity for growth, 
only that capacity results in a development along somewhat different 
lines. What I mean can best be studied by observing the conduct of 
individual units of these. higher tissues, either in the attempt at 
restoration of a muscle or nerve after section, or again, by a study of 
the processes occurring in glandular structures during the course of 
an inflammation that is not too intense. Severe inflammation lead- 
ing, as it does, to active cell destruction is outside our purpose. Now, 
the most prominent characteristic of a nerve or muscle fibre present 
in the attempt at recovery after injury is the multiplication of the 
nuclei of each unit, a multiplication often regarded and spoken of as 
a degeneration, and indeed not unfrequently such multiplication pre- 
cedes the actual disintegration of the unit. This multiplication, 
which I have elsewhere spoken of as " reversionary degeneration," is, 
I hold, an indication of a reversion to a more primitive type of cell, 
and indeed in the case of muscle Metchnikoff and others have shown 
that the individual nuclei resulting from this nuclear division may 
surround themselves with protoplasm and may pass away as simple 
embryonic cells, so that the whole muscle fibre becomes completely 
disintegrated. The process here is one of what may be also termed 
vital disintegration. The same principle that is shown here is to be 
seen at work in glandular structures. Take, for example, a case of 
parenchymatous nephritis. If this be acute the cells of the tubules 
swell up, show vacuolation and other signs of acute degeneration of 
the cell substance, with failure of the nuclei to stain properly (or to 
put it in other words, diminution of the chromatin of their nuclei), 
and the cells are cast off. With a lesser degree of inflammation the 
process is very different; we find here that the cells proliferate, but 
at the same time these new cells do not show the full adult character, 
their nuclei it is true stain intensely, but their bodies are small and 
cubical, their characters become more nearly allied to those of the 
cells in the developing kidney. 
Or take the liver. Here in chronic inflammation we find the same 8 
rule to obtain. If we study the comparative anatomy and the develop- 
ment of this organ we discover that it has arisen from a collection of 
separate acini or finger-like gland follicles. In the adult liver it is 
impossible to convince oneself of this fact; the cells seem to be 
arranged essentially in lobules around the branches of the hepatic 
vein; nevertheless the bile capillaries represent the lumina of the 
original or primitive gland follicles, and with chronic inflammation, 
as we see in case after case of cirrhosis, at the periphery of the lobules, 
the liver cells show the tendency to proliferation, with associated 
diminution in size; their nuclei stain as intensely as do those of 
neoplasms, so full are they of chromatin, and these small embryonic 
cells arrange themselves in a tubular manner, so that we have the 
appearance of numerous irregular winding ducts running through the 
new connective tissue formation at the periphery of the lobules-a 
reversion towards the primitive structure. 
Still more instructive is the condition seen in the lung in chronic 
inflammation. In any case of chronic interstitial pneumonia [this 
term interstitial pneumonia is unsatisfactory, and a better one is 
chronic productive pneumonia, for the inflammation affects the paren- 
chyma equally with the interstitial substance]-in any such case, I 
say, we observe that the result of continued inflammation is to lead 
to a modification of the epithelium lining the alveoli, so that instead 
of this being flattened and indistinguishable it is represented by a 
layer of small cubical cells in all respects resembling the cells lining- 
future air sacs in the lung of the embryo. 
In all these cases, therefore, we see this law holding good, that with 
chronic irritation of moderate intensity the cells of highly organized 
tissues tend to proliferate and to assume a more embryonic type. So 
true is this that time and again -we pathologists are completely at a 
loss to give a full diagnosis. We receive from the gynaecologists, for 
example, scrapings from a womb with a history that there has been 
long-continued endometritis, and cancer is suspected. We receive from 
the surgeons portions of tissue taken from the edges of chronic ulcers, 
and are asked to decide if they be epitheliomatous, and in these and 
similar cases of so embryonic a type is the cell overgrowth, that it is 
impossible for us time after time to declare whether we are dealing 
with inflammation pure and simple or with actual cancerous tissue. 
I must confess that when I send in the reports upon such cases I still 
feel apologetic, I feel that the surgeons and gynaecologists have the 
idea that a pathologist ought to know these matters and ought to be 
able to give an assured diagnosis. I feel that the said surgeons and 
gynaecologists will when they read such reports complain that after 9 
all I, the pathologist, am a very weak reed to have to lean upon. 
And I am glad that now, when I have no doubtful specimen before 
me to report upon, I can point out to the surgeons and the gynaecolo- 
gists the state of affairs as it actually is, namely, that it is at times 
impossible to distinguish between chronic inflammatory and malignant 
tissue. And the reason, gentlemen, why it is impossible thus to dis- 
tinguish between the two is that the difference between them is purely 
one of degree. 
There can be no doubt that at times this inflammatory hyperplasia 
of gland cells-this development of embryonal or sub-adult gland 
tissue-passes on imperceptibly into cancer. Although it may be urged 
that in all cases of cancer the history of previous chronic inflammation 
cannot be obtained, this fact that antecedent chronic inflammation at 
times either escapes detection or is not present, in nowise weakens 
what is here stated, namely, that many cases of chronic irritation and 
long continued inflammation of moderate intensity, affecting epithelial 
and glandular tissues merge into carcinomatous manifestations. And 
so far as I can see, the line separating the one condition from the 
other, is that which separates continent from incontinent cell growth. 
In chronic inflammation as seen, for example, at the edge of an ulcer 
we have a condition of increased blood supply and increased nutrition, 
and as a result we obtain that cell proliferation already described, 
associated with reversion to embryonic character, or almost I might 
state it otherwise and say, that we have reversion to embryonic 
character with associated embryonic powers of rapid cell multiplica- 
tion, for the two conditions are inseparable. The only distinction 
between the inflammatory and the cancerous growth is this, that in 
chronic inflammation remove the cause of the irritation and the pro- 
cess of abnormal cell growth comes to an end. In cancer, the cells 
from frequent and rapid multiplication in a more or less embryonic 
state have gained the habit of growth, of unrestrained growth. It 
may be also that the vessels going to the region, from long dilation 
remain distended or have acquired persistent distension ; so that even 
when the primary irritant is removed the part continues to receive 
nourishment in excess of physiological needs. This, together with 
paralysed nerve control, may well be factors leading to the first men- 
tioned condition, but before all, it seems to me, that 
there is to be recognized this assumption of the 
habit of growth, so that once fully started upon 
the road of proliferation the cells continue to 
multiply utterly irrespective of the needs of the 
organism. 
It may be said that this is an assumption on my part, and not 10 
necessarily on the part of the cells, but I would ask you to consider a 
little before arriving at such a conclusion. The cells of the body, we 
know, are capable of acquiring other habits ; we know for example 
that they can acquire a tolerance for sundry drugs ; we believe also 
now-a-days that acquired immunity for disease is essentially due to 
the acquirement of another habit, to the accustomance on the part of 
these cells to the presence of small or weak doses of the products of 
pathogenic micro-organisms, resulting in the descendants of these cells 
at a later date being able to withstand, if not actually to be attracted 
to the products of these same bacteria when present in a more con- 
centrated form. But apart from this support from analogy which, it 
may be said, is at the most doubtful, we have in the cancer cells clear 
indications of the assumption of this habit. There is in the first 
place the undoubtedly embryonic appearance in the cells. Now it is 
during embryonic life where, under physiological conditions, the cells 
possess this appearance, that they possess also most characteristically 
the power of frequent multiplication, that they poss.ess very clearly a 
physiological habit of growth. Again there is to be noticed the 
excessive amount of nuclear chromatin. This increase in the amount 
of chromatin in the nuclei is under ordinary physiological conditions 
an indication that the cells are undergoing, or are about to undergo, 
multiplication. In an ordinary cancer, what immediately strikes us, 
is that all the cells in an alveolus, more especially towards the grow- 
ing edge of the cancer mass, show a peculiarly intense nuclear 
staining. Thirdly, the irregular character of the mitosis or indirect 
cell division observable in cancer cells may in itself be accepted as an 
indication that the impulse towards division is so strong that the 
nuclear masses often break into three stars instead of two, or throw 
off redundant masses. And lastly, what may be termed the intense 
vitality of the cancer cells is again a character of young growing cells. 
It is common to speak of the cells of malignant tumours as being 
endowed with low vitality. Nothing can be more incorrect. It is 
indeed true that the more internally situated cells of a new growth 
exhibit frequent evidence of either necrosis or various forms of 
degeneration. But those changes are surely to be ascribed not to 
the lack of vitality of the cells, but to the serious disturbance to the 
blood supply of the central region of a tumour which almost inevitably 
follows its eccentric growth. That growth and extension in spite of 
the pressure of the surrounding organs must also be associated with 
pressure effects upon the nutrient vessels of the more central area. 
Compare the cancer cells with those of the surrounding tissues. The 
latter certainly undergo necrosis and absorption, while the invading 11 
cancer cells show every sign of active growth. The power that these 
cancer cells have for multiplying in new environment is in itself an 
evidence of heightened vitality. 
It is true that there are certain layers of cells in the normal body 
which possess a somewhat closely allied intense vitality. The 
botanists have for long recognized the existence of similar layers in 
the higher plants and have spoken of them as the "cambium" or cam- 
bium layer. I do not know whether with the advance of the gentle 
science any other name has been given to the strata of the perma- 
nently embryonal cells. It would be well if in physiology we had 
some term denoting the collections of cells of this nature. It is 
owing to the existence of these cell layers that we are able to 
transplant skin and periosteum. In the former the layer in question 
is the lowest layer of the stratum Malpighi, which throughout life 
exists in a permanent embryonal condition and which is constantly 
presenting cell division, and developing new individuals to help to 
form the epidermis and to replace the scales of dead cells that are 
constantly being thrown off. In the latter also we have present an 
analogous layer of permanently embryonal cells. These layers may 
be said to present throughout life the habit of growth, and it is inter- 
esting to notice how peculiarly liable these very cell layers are to 
become the seat of unrestrainable or unrestricted growth, to mani- 
fest malignancy. But under physiological stimuli this excessive growth 
does not show itself, and under physiological conditions when trans- 
planted, while the vitality of these cells is sufficient to permit of their 
proliferation when placed in similar environment, when placed in 
abnormal environment they die, just as any other healthy tissue dies 
and is absorbed when it is transplanted either subcutaneously or 
intraperitoneally into another individual. The cancer cells accom- 
panying this power of unrestricted growth have a vitality so intense 
that when transplanted into widely different regions of the host from 
the original primary seat of growth they still are able to proliferate, 
and indeed this intense vitality renders it not impossible that occa- 
sionally cancer cells transplanted from one individual may grow in 
another; but it must be remembered that it is wise not to regard this 
as a phenomenon of true infection, any more than it is wise to con- 
sider the grafting of skin from one individual to another a true 
infection. 
Finally, let me say that that theory is most worthy of acceptance 
which while being the simplest embraces and explains the largest 
number of phenomena. As I have shown, the parasitic theory is too 
limited to be satisfactory. Parasites may possibly be one cause of 12 
chronic irritation and of originating the habit of incontinent cell 
growth. At most they are one cause ; and till their life history has 
been mastered, till they are found in every cancerous specimen exam- 
ined with sufficient care, they cannot be regarded as explaining every 
case of carcinoma. 
The theory held by not a few that a weakening of the basement 
membrane lining the stratum Malpighi and gland alveoli is to be con- 
sidered as explaining why the epithelial and gland cells invade the 
surrounding structures, is unsatisfactory in that it is only applicable 
to carcinomata, and has no bearing upon the development of malig- 
nant connective tissue growths. It is unsatisfactory, again, because 
we cannot recognize the actual point of weakening of the membrane. 
We can and must recognize on the other hand the condition of intense 
and active growth of the cancer cells and of the pre-cancerous cells, if 
I may so describe them. And it is not difficult to assume that the 
very intensity of this growth, coupled with the vitality of the new 
cells which does not permit them to undergo easy atrophy, so long as 
there is abundant nutrition, is capable of causing so much pressure 
within the gland alveoli that the weakening of the basement mem- 
brane is purely secondary to the vigorous cell growth, so that this 
habit of growth can explain alone the bursting of the caneer cells 
through the membrane and their invasion of the adjacent lymphatics. 
The theory of a seminium as started by Virchow and elaborated by 
Creighton and others, while very taking, requires if pushed to its 
logical conclusion a seminium or seminal invasion for every prolifer- 
ating cell in the body. True, each of us as a result of the habit of 
growth of one cell may be regarded as a motile tumour, and certainly 
in our case there was a primary seminium starting the growth, never- 
theless comparative studies show that such is not necessary for the 
development of every organism or even for the development of sundry 
organisms high up in the scale of animal life. Add to this that the 
specific seminium in cancer has never been discovered. 
Cohneim's celebrated theory has been so twisted about by various 
writers upon carcinoma, and has been made to do such yeoman ser- 
vice that it is necessary that I should here refer to it. But the 
embryonal cell vestiges upon which it is based are only useful in 
their restricted sense as explaining the rarer forms of cancer in which 
the condition of glandular or epithelial malignant growth apparently 
originates in tissues containing normally no glandular or epithelial 
substances. In its wider application it harmonises with the theory 
that I have placed before you, inasmuch as it demands as the initial 
stage of cancel* growth the existence of embyronic cells. 13 
It will be seen that the theory that I have laid before you by 
granting to the cancer cells the habit of tenacious and incontinent 
growth explains the assumption by the cancer cells of embryonal 
characters, explains also the overgrowth of these cells, the bursting 
through the basement membrane, the growth along surrounding lymph 
spaces, and even in the course of the blood vessels, and, with this, 
growth similar in character to the primary development at a distance 
from the primary seat, and so explains the formation of metastases, 
in fact the theory includes and explains all the essential characters 
of malignancy. 
So far in laying before you these suggestions upon the nature of 
malignant growth, I have dwelt more especially upon the influence of 
chronic inflammation of moderate intensity in leading up to neoplastic 
tissue formation. But it may well be asked if it is accessary to 
assume that chronic inflammation of moderate intensity is the sole 
factor to be recognized as originating the habit of incontinent growth. 
A theory starting from the ground that malignant growth is. always 
preceded by a stage of long continued slight inflammation is indeed 
untenable, clinical evidence does not warrant a premise of this nature. 
The most that can be said is that, comparing the histories we obtain 
in connection with the development of malignant neoplasms which 
are visible and more or less superficial, with those obtainable in con- 
nection with cancer and sarcomata of deep seated organs, we find a 
very much greater proportion of statements of previous injury and of 
chronic irritation in the former than in the latter class. I need but 
call your attention to the almost constant history of irritation obtain- 
able in cases of cancer of the lips or of the tongue, and recent studies 
would indicate that-in the case of cancer of the breast for example- 
the more fully the previous history of the patient is studied the more 
frequently do we obtain evidences of injury inflicted upon the region 
which has become the primary focus of cancer. (Here, however, it is 
to be noted that the injury may have been inflicted long years pre- 
viously.) But granting all this there remain cases in which it is not 
possible to demonstrate the previous action of chronic irritation, and 
these cases are sufficiently numerous to render it, I hold, unsafe to 
attempt to employ the argument by analogy and to assume that 
though unnoticed there did exist a pre-cancerous irritative stage. 
If we examine the conditions associated with slight chronic irrita- 
tion we cannot fail to notice that with the overgrowth of the tissues 
there is an accompanying condition of increased nutrition. Take for 
instance the edge of a chronic ulcer. The zone of the increased 
epithelial and connective tissue growths is at the same time a zone of 14 
dilated vessels. That dilatation and the increased blood flow in the 
region may safely be said to have been brought about not so much by 
the demands of the peripheral tissue as by the central irritation, or in 
other words it would seem that, as a consequence of focal irritation, 
there is induced a dilatation of the vessels and increased blood flow 
extending beyond the area directly affected by the irritant. If this 
be so (and there is much to be said in favour of the view) then not a 
little of what are regarded as the effects of chronic irritation of a 
mild type may rather be assigned more immediately to over-nutrition 
-to a blood supply beyond the physiological needs of the region. 
And other cases in which there is such nutrition in excess of physio- 
logical needs unassociated with inflammation may likewise tend to 
the development of neoplastic growths. 
We here approach a department of pathology that has been little 
worked at, and I must needs speak with caution. Indeed I would 
only hint that very possibly after the climacteric when retrogression 
of certain issues becomes increasingly manifest, with the absorption 
of certain of the components of sundry tissues other components of 
these same tissues gain a relatively greater amount of nourishment, 
and more especially where by injury (it may have been years pre- 
viously) a certain amount of deformity or altered relationship of 
parts, a certain amount of instability, has already been introduced, 
there we have an association of factors peculiarly favourable to the 
acquirement of a tendency towards irregular and sub-adult cell growth 
-of a tendency towards the assumption by sundry cells of the afore- 
said habit of incontinent growth. While upon this subject, upon the 
liability of cancerous growth to occur at or about the climacteric, I 
may point out that the cell changes accompanying the involution of 
the tissues at the change of life are reversionary in character, they 
resemble to a certain extent the changes which I have described as 
accompanying chronic inflammation. 
Before closing this paper, I must needs impress upon you that there 
is one factor which I have not touched upon, namely, modified nerve 
control over the tissue. This may be a factor in the development 
of neoplasms, but beyond the fact that recent observations seem to be 
proving more and more conclusively the intimate relationship between 
the nervous system and the fixed cells of the body, there is nothing 
that can safely be said with regard to the matter ; there are no experi- 
ments or direct observations at all bearing upon it. It is safer, 
therefore, not to do anything beyond referring to its very possible 
existence, and pointing out that it is wise not to leave it wholly out 
of account. 15 
To return now to the substance of my opening remarks. If the 
suggestions (and I hardly like to venture to call them more than 
suggestions) which I have thrown out have any solid basis, then it 
would appear probable that the advance in interference with cancer 
must proceed directly along the lines that it is at present taking in 
the hands of the surgeons, namely, the duty of the surgeon must be 
to recognise the existence of new cell growths at the very earliest 
moment, and more, now that operation is so robbed of its previous 
terrors, and that parts can be removed with so little disfigurement 
and so little danger of sequelae, it becomes the duty of the wise sur- 
geon to remove every neoplasm, benign as well as malignant, at the 
first opportunity. There is no valid reason for retention, there 
is the possibility, even if it be but distant, that the benign growth 
may assume malignant properties. Destruction of the cancerous 
tissue at the earliest moment, whether by the knife oi' by the adminis- 
tration of substances which excite a specific action upon the cells,- 
this alone, I cannot but hold, is' what we have to recognize as the 
procedure at which to aim.