(REPRINTED FROM "THE LENS.") 136 
The Cell. 
[July, 
THE CELL. 
I. THEORIES OF CELL DEVELOPMENT. 
From a very early period in the history of medicine the idea 
prevailed that there must be some anatomical unit, some elementary 
part or particle, which, whatever might be its form or size, must be 
regarded as the true seat and home of vitality. Without the aid of 
optical instruments, or even of the dissector's scalpel, and at an age 
of the world when philosophy was but a tangled maze of fancies; 
when men, with curious persistency, shunned the plainest truths 
and blindly groped in darkness, even then the conviction seems to 
have forced itself upon many that, underlying the various tissues 
and organs of the body, there must be some vital element common 
to them all, and from which they were all originally differentiated. 
And this idea was not so much the product and result of close and 
vigorous analytical thought as it was the outgrowth of an inevitable 
necessity, namely, the necessity for a somewhere and a something 
which should serve as a biological starting-point. Hence we find 
Fallopius (1523-1562), Borellus (1656), Haller (1757), and others 
constructing their rude, and to us preposterous, theories in answer 
to demands which were irresistible. But these early theories have 
for us little value or interest, save as antiquaries, since none of 
them clearly recognize the cell as the ultimate anatomical element. 
To the histologist of the present day it seems strange, and indeed 
almost incredible, that so many years should elapse between the 
real discovery of the cell and the comprehension of the one great 
fact that this little body is the starting-point of all development. 
There seems to be little doubt that Borellus actually saw the cell as 
long ago as 1656, since, as Dr. Tyson remarks, "he describes pus- 
corpuscles as animalcules, and even says he saw them delivering 
their eggs."* In truth, it is more than probable that what Borel- 
lus believed to be the act of "delivering eggs" was really the process 
of cell development by "budding" or "gemmation," so that this 
very important discovery was made two centuries before it was 
announced. 
The first attempt at the construction of a systematic theory con- 
cerning the cell and its origin, seems to have been that of Wolf, 
about the year 1759. From this time, therefore, the cell may be 
* The Cell Doctrine, p. 16. 1872.] 
The Cell. 
137 
said to have a connected history; although it is quite common to 
regard cell history as commencing many years later, with Schleiden 
and Schwann. Although the name of Wolf was wellnigh for- 
gotten, and would have so remained but for the magic touch of the 
brilliant but erratic Huxley,* his doctrines have exercised no little 
influence upon the thoughts and writings of many of his followers. 
We shall presently see that Wolf is the real, while Schleiden is only 
the putative, father of that wayward child, free or spontaneous cell 
development. 
If we carefully analyze the various cell theories which have ap- 
peared from the time of Wolf until the present,-and which for 
convenience we may style "modern" theories,-we shall find, first, 
that they are all hinged upon different conceptions concerning cell 
development; and secondly, that these different theories may be 
reduced to four classes, namely : 
(yz.) Theories which recognize free cell development. 
(z$.) Molecular or globular theories. 
(y.) Theories which locate developmental power outside the nu- 
cleus. 
(y/.) Theories which confine developmental power to the nucleus 
alone. 
No sooner was the cell recognized as the true and universal agent 
of development, than the importance of understanding its mode of 
development was seen ; hence we at once encounter theories of 
cell development, and for many years these followed one another in 
rapid succession. 
(zz.) Free Cell Development.-This doctrine has at least one posi- 
tive merit, namely, boldness. Commencing, as I have already 
intimated, with Wolf in 1759, it has encountered various ups and 
downs, until, at the present time, it is really the keystone of the 
doctrine of "spontaneous generation," so vigorously defended by 
Dr. H. Charlton Bastian, of London. According to Wolf, "every 
organ is composed at first of a mass of clear, viscous, nutritive fluid, 
which possesses no organization of any kind, but is at most com- 
posed of globules."f Subsequently cells are developed, but they 
are "mere cavities, and not independent entities; organization is 
not affected by them, but they are the visible results of the action 
of the organizing power inherent in the living mass, or what Wolf 
* British and Foreign Medico-Chirurgical Review, October, 1853. 
f Huxley, loc. cit. 138 
The Cell. 
[July, 
calls the vis essenhalis (Huxley;. 1 his simply amounts to saying 
that the cell is merely a passive, not an active, body; that it is only 
matter thrown into a convenient form for building material, as clay 
is thrown into the form of bricks for the same purpose, while the 
real builder is the so-called "vis essentialis" resident in the "clear, 
viscous, nutritive fluid." Twenty years ago it was necessary to 
combat this doctrine, but at the present day it does not even merit 
the compliment of criticism. 
We encounter the next phase of free cell development in con- 
nection with the doctrines of Schleiden. This observer - the first 
to comprehend the fact that the cell is the true and ever-present 
basis of developmental action in vegetable tissues - acknowledged 
two distinct methods of cell growth; one of which, the so-called 
" exogenous free cell formation," must be regarded as a true creative 
act, while the other (" endogenous cell formation' ') is a mere continu- 
ance of the process, or cell multiplication. The accompanying 
figure (Fig. i), copied from Virchow,* 
is intended to illustrate the method 
of free cell development according to 
Schleiden. In the midst of a perfectly 
structureless, clear, transparent fluid 
{blastema, cytoblastema} granules are 
first seen, "some of which increase in 
size and assume the form of a minute 
vesicle, the nucleus of the future cell. 
On the addition of water to this, gran- 
ules become apparent in its interior, 
and one of these, larger than the rest, 
appears to be the nucleolus. Around 
the nucleus, as is generally stated, the 
cell membrane is developed, and thus 
the cell is completed. "f Virchow's 
account of Schleiden's theory does not 
exactly agree in terms \n\X\s the one quoted above, although the prac- 
tical difference amounts to nothing; it is as follows "According 
to the view which was put forward in the first instance by Schleiden, 
and accepted by Schwann, the connection between the three coex- 
istent cell constituents was long thought to be on this wise,-that the 
Fig. i. From Schleiden (after Vir- 
chow). - Contents of the embryo 
sac of viciafaba,, soon after impreg- 
nation. 
a. Granules floating in a clear fluid 
of gum and sugar, the so- 
called "blastema" or "cytoblastema"). 
b, c. Agglomerated granules, forming 
'cytoblasts" or nuclei. 
<Z, e. Fully-formed cells, showing the 
Completion of the process of spontaneous 
development. 
* Cellular Pathology, p. 36. f Peaslee's Human Histology, p. 120. 
J Cellular Pathology, p. 35. 1872.] 
The Cell. 
139 
nucleolus was the first to show itself in the development of tissues 
by separating out .of a formative fluid {blastema, cytoblastemd), that 
it quickly attained a certain size, that then fine granules were pre- 
cipitated out of the blastema and settled around it, and that about 
these then condensed a membrane. That in this way a nucleus was 
completed, about which new matter gradually gathered, and in due 
time produced a little membrane (the celebrated 'watch-glass' 
form)." In the one case, granules are first produced, and, by their 
aggregation, the nuclei are afterwards formed; in the other, the 
nuclei take the precedence, the granules being a secondary product. 
Seeing that the nucleus was discovered several years previously 
(1833) by Brown, of Edinburgh, and that Schleiden had conferred 
upon it the name of " cytoblast" or "cell-bud," thus directly im- 
plying his belief in its importance in relation to cell growth, it is 
more thah probable that Virchow's account is the more correct one. 
Schwann, whose observations seem to have been confined chiefly to 
animal structures, adopted the views of Schleiden concerning the 
development of vegetable cells, and applied them to the genesis of 
the cells of animals. He "was of opinion that the extracellular 
formation of cells-that is, their development in free blastema-was 
the most frequent mode of their production in animals."* At this 
period, therefore, the theory of free or spontaneous cell develop- 
ment was generally accepted by histologists; and, seeing that 
Schleiden and Schwann gave to this notion the support of their 
great authority, it is by no means a matter of surprise that it found 
general favor. 
Passing by the more recent advocates of spontaneous cell-growth, 
especially Bennett, of Edinburgh, Carpenter, and Todd and Bow- 
man,f with the remark that they are simply recasts of the views of 
Schleiden, we come to that phase of spontaneity which, if estab- 
lished, fully demonstrates the possibility, and, indeed, the constancy, 
of the spontaneous origin, not of individual cells alone, but of 
living beings. 
It does not come within the limits or scope of the present article 
to review the history of the long, and as yet unsettled, contest 
concerning the spontaneous evolution of cells, or of those simple 
* Stricker's Histology, vol. i. p. 34. 
t "The Physiological Anatomy and Physiology of Man," edition of 1857. It is proper to 
observe that in the last edition (1866), now issuing in parts under the editorship of Dr. Lionel 
Beale, the well-known cell theory of the latter is presented. 140 
The Cei 
[July, 
aggregations of cells which form the lowest types of living things. 
For a very complete review of this subject, I take great pleasure in 
referring to the essay by Prof. J. C. Dalton, in the New York 
Medical Journal for February, 1872. The doctrine of spontaneous 
generation was generally believed in by the ancients; was dis- 
proved, in all except certain "exceptional" cases, by Regnier de 
Graaf (1672) and Von Baer (1827); was revived by Needham 
(1748), and again controverted by Spallanzani (1775); was vigor- 
ously assailed by Schultze and Schwann (1836 and 1837), and for 
twenty years after the period last mentioned was generally abandoned 
by scientists as untenable. "The production of living beings with- 
out parents was a theory admitted to have no reasonable basis for its 
support, and was regarded simply as a curious relic of antiquity."* 
But in the year 1858 the doctrine of spontaneous evolution was 
revived by Pouchet, of France, as a sort of buttress to support the 
conclusions to which he was forced by the revelations of modern 
geology. Pasteur, however, and several other members of the 
French Academy, repeated Pouchet's experiments with entirely 
negative results, and again this troublesome ghost seemed upon the 
point of being laid, when Prof. H. Charlton Bastian, of London, 
published his series of experiments, and announced himself as "con- 
tent" and "justified" in "believing that living things may and do 
arise de novo."\ According to Bastian, various unicellular organisms 
are pretty constantly developed in boiled and hermetically sealed 
infusions of hay, turnip, etc., and also in certain saline solutions 
treated in like manner. The reader is referred to Nature, vol. 
ii. p. 170 et seq., and also to Dr. Bastian's work, the " Beginnings of 
Life," recently published, for an extended account of his very in- 
teresting experiments, and the accompanying illustrative figures. 
He claims to have demonstrated that monads, bacteria, torulae, 
vibrios, leptothrix filaments, fungus spores, and various unclassified 
organisms of cellular structure, are developed from solutions of or- 
ganic and saline substances absolutely destitute of living germs; 
hence they must originate de novo. This, of course, is the very es- 
sence of free cell development, or rather it is something more than 
that, since it confers upon any solution of organic or saline matters 
containing the chemical elements of protoplasm, the power not 
only to generate cells, but to spur them forward to that subsequent 
* Dalton, loc. cit. 
f Nature, vol. ii. p. 228. 1S72.J 
The Cell. 
141 
differentiation which results in the (not lawful, but) lawless creation 
of living beings. It carries us back to the days of Wolf, and sub- 
stitutes for specific germs, endowed with vital force for a specific 
and unchangeable purpose, a something (which we may as well 
call a "vis essentialis" as anything else) by virtue of which dead 
matter is brought to life, boiled hay is made a creator, and solutions 
of salts forget the laws of crystallization and take to themselves 
the power of the genesis of new and unheard-of living (!) beings. 
For my own part, I cannot accept the doctrine of spontaneous cell 
formation in any form or to any extent, or the doctrine of hetero- 
genesis (which is the same thing in different dress), until, like 
Pouchet, I shall be blessed with that boundless faith which sees in 
spontaneity the very beginning of animated existence, and in the 
higher orders of beings, even up to man himself, only the result of 
"the ascending development of organized beings upon the globe." 
(A) Globular or Molecular Theories.-The globule theory, ac- 
cording to Virchow, was partly the outgrowth of the reaction 
against the fibre theory of Haller, partly the result of optical illu- 
sions from the unskillful use of microscopes which, at the very 
best, were infinitely inferior to those of the present day. It is 
difficult to understand the precise relation of the globule or mole- 
cule theory to the cell in the minds of the earlier writers, for the 
following reasons: First, several observers, following Leuwenhoek, 
believed that the tissues were developed directly from globules, 
without the intervention of cells; secondly, the terms "globule," 
"molecule," and "granule" were, and indeed still are, so inter- 
changeably used, especially among the Germans, that neither term 
seems to have, or to have had, any very definite meaning; and 
thirdly, it is, to say the least, very probable that cells were fre- 
quently described as globules, and globules were sometimes described 
ascells. Although the terms "globule," "granule," and "mole- 
cule" are now understood to refer to bodies which are morphologic- 
ally, and possibly chemically, distinct, they usually seem to have 
indicated to the earlier, as well as to some recent, writers, bodies 
smaller than cells, but having to cells a developmental relation. 
The writings of Milne-Edwards gave general currency to the 
globule theory; but he does not seem to have deemed it necessary 
that globules should be converted into cells before proceeding to 
form tissues; but, as pointed out by Tyson, "there is little doubt 142 
The Cell. 
[July, 
but that many of these so-called globules described by Edwards 
were really cells, seen with indifferent instruments, and further 
distorted by the glare of direct sunlight."* 
On the other hand, Arnold and Baumgartner recognized the cell 
as an intermediate stage of develop- 
ment. "A cell was considered to be 
produced by the globules arranging 
themselves in a spherical form, so as 
to constitute a membrane, within which 
other globules remained, and formed 
contents."f But they also believed 
that fibres were formed of elementary 
granules drawn up in a line, as shown 
in the accompanying diagram (Fig. 2). 
Concerning the so-called "invest- 
ment" or "cluster" theory, which for 
a time was pretty generally accepted, Virchow says "the upholders 
of this theory imagined that originally a number of elementary 
globules existed scattered through a fluid; but that, under certain 
circumstances, they gathered together, not in the form of vesicular 
membranes, but so as to constitute a compact heap (mass, cluster,- 
Kliimpchen), and that this globe was the starting-point of all further 
development, - a membrane being formed outside and a nucleus 
inside by the differentiation of the mass by apposition or intussus- 
(Fig. 3). This theory 
is a most singular conglomera- 
tion of truth and error: of truth, 
in that it concedes what we now 
know so well, namely, that the 
membrane is not a necessary 
part of the living cell; of error, 
in that it practically recognizes 
free cell development. 
Probably the most strenuous and persistent advocate of the 
globular (or, to adopt his own terminology, the molecular) theory 
at the present time is Prof. Bennett, the eminent pathologist of 
Edinburgh. His theory is best given in his own words: "The 
Fig. 2.-Diagram of the globular 
THEORY, ACCORDING TO ARNOLD AND 
Baumgartner (after Virchow). 
a. Fibre composed of elementary 
granules (molecular granules) drawn 
up in a line. 
b. Cell with nucleus and spherically- 
arranged granules. 
Fig. 3.-Diagram of the investment or 
cluster theory (after Virchow). 
a. Separate elementary granules. 
b. Heap (cluster) of granules. 
c. Granule cell, with membrane and nucleus. 
* The Cell Doctrine, p. 24. t Virchow, Cellular Pathology, p. 53. 
J Op. cit.,p. 53- 1872.] 
The Cell. 
143 
ultimate parts of organization are not cells nor nuclei, but the 
minute molecules from which these are formed. They possess 
independent physical and vital properties, which enable them to 
unite and arrange themselves so as to produce higher forms. Among 
these are nuclei, cells, fibres, and membranes, all of which may be 
produced directly from molecules. The development and growth 
of organic tissues is owing to the successive formation of histoge- 
netic and histolytic molecules. The breaking down of one substance 
is often the necessary step to the formation of another; so that the 
histolytic or degenerative molecules of one period become the his- 
togenetic or formative molecules of another."* On the succeeding 
page he adds, "As to development, the molecular is the basis of all 
tissues. The first step in the process of organic formation is the 
production of an organic fluid; the second, the precipitation in it 
of organic molecules, from which, according to the molecular law 
of growth, all other textures are derived, either directly or indi- 
rectly,"-that is, with or without the intervention of cells. (Figs. 
Fig. 4 (after Bennett). 
a. Molecular structure of the scum on its first appearance in an annual infusion. 
K b. The same six hours afterwards; the molecules separated, and the long ones (so-called 
vibrios) in active movement. 
c. The same on the second day. 
d. Filaments (so-called spirilla) formed by aggregation of the molecules in the same scum on 
the third and fourth days, all in rapid motion (800 diameters). 
Fig. 5 (after Bennett). 
a. Nuclei imbedded in a molecular blastema. 
b. Young fibre cells formed by the aggregation of molecules around the nuclei of a. 
c. Cancer cells,-one with a double nucleus. 
d. Histolytic or so-called granule cells, breaking down from fatty degeneration (250 diameters). 
4 and 5, copied from Bennett's Lectures, are designed to illustrate 
his doctrine.) 
* Bennett's Lectures, p. 118. 144 
The Flora of Chicago and Vicinity. 
[July, 
It will readily be seen that the theory of free cell development, 
as originally stated by Wolf and modified by Schleiden, and the 
globular or molecular theory, are, practically, one and the same 
thing,-the difference being in terms, not in results. Both mean 
spontaneous cell formation. Both alike deny that a cell is necessary 
to the development of a new cell; but, while the former comes 
squarely to the point and says what it means, the latter makes use 
of the molecule as a sort of a sugar-coat for that unpalatable dose, 
spontaneity. 
The remaining theories concerning cell development, according 
to the classification already given, will be considered in the next 
number of The Lens. 
I. N Danforth, M.D., 
Pathologist to St. Luke's Hospital. 
Chicago. THE CELL. 
11.-theories of cell development. 
(c.') Theories which locate Developmental Power outside the Nu- 
cleus.-According to the older notions of the perfect cell, it con- 
sists of five distinct elements, namely: 
"(1) The cell wall. 
(2) Contained fluid. 
(3) Granules floating in the fluid. 
(4) The nucleus. 
(5) The nucleolus."* 
According to Virchow, the typical cell includes always the "cell 
wall," " cell contents," and "nucleus;" the nucleolus being gen- 
erally, but not invariably, present.f 
The nucleus and nucleolus must be and are (and generally were) 
regarded as structurally and functionally identical,-the latter being 
simply the youngest portion of the former. J 
Excluding, then, for the present the nucleus (and, of course, the 
nucleolus), we have three elements, which, collectively, form the 
periplast of Huxley, the formed material of Beale, the sarcode of 
Dujardin, the protoplasm of Max Schultze, and what is generally 
understood as the cell contents of other authors. 
At the present time, the power of cell multiplication is pretty 
generally believed to reside in the nucleus; but some possible ex- 
ceptions are admitted among the lowest orders of living beings, as 
we shall presently see. Some of the earlier writers, however, seem 
* Peaslee's Human Histology, p. 114. 
+ Virchow, Cellular Pathology, p. 30 et seq.-Since the publication of this work, Virchow has 
modified his views by admitting that the cell wall is not necessarily and constantly present. 
J It must be remembered that this description applies only to the cell which is no longer 
living; for it is a singularly recent discovery that dead cells are no more like living cells than 
dead men are like living men. I shall allude to this point more at length in a future paper. 1872.] 
The Cell. 
213 
to have looked upon that portion of the cell outside the nucleus as 
at least of equal importance with the latter in its relations to cell 
multiplication. But it must be confessed that it is necessary to 
speak somewhat guardedly upon this point, since it is impossible to 
extract a definite and certain meaning from the language employed 
by some of the earlier observers, and others appear to have scarcely 
known what they believed themselves. Moreover, the mania for 
word-coining which early crept into the domain of cytology (and 
which, by the way, has not yet crept out again) has also increased, 
instead of lessening, the confusion. The same word is frequently 
applied by different writers to different portions of the cell: for 
example, the word "protoplasm" has at various times, and in 
the service of various authors, carried with it so many meanings 
that it now has scarcely any meaning at all. It follows from all 
this that every man has to be, to a considerable extent, his own 
interpreter; and it would not be surprising if my understanding of 
the language employed by some of the writers to whom I shall 
refer should be different from the interpretation of some of those 
who may chance to read these pages. 
I am not aware that the genetic function of the nucleus has ever 
been denied ; indeed, the name conferred upon it by Schleiden 
("cytoblast" or "cell-bud," the budding or growing cell), shortly 
after its discovery by Robert Brown, expressly implies his belief in 
its power of development; a belief, as we shall presently see, which 
has now become wellnigh universal. 
Fissiparous cell development, or multiplication by division, as 
primarily understood, seems to have been regarded as commencing 
at the periphery of the cell. Schwann, with some hesitation, ad- 
mitted a mode of cell multiplication by the "growth of partition- 
walls across the old cells." No mention is here made of the divi- 
sion of the nucleus, but the so-called cell wall was the active agent 
in the accomplishment of the process. Schwann was led to half 
doubt the accuracy of his judgment, because Schleiden supposed 
that what appeared to be bipartite cell development was in reality 
"an illusion, inasmuch as the young cells might escape observation 
in consequence of their transparency, and at a later stage their 
line of contact would be regarded as the partition-wall of the parent 
cell."* That mode of cell multiplication to which Henle gave the 
name of "segmentation" (a term now generally applied to the 
* Tyson, "The Cell Doctrine," p. 38. 
Vol. I.-No. 4. 214 
The Cell. 
[Oct. 
process which first takes place in the fecundated ovum) was prob- 
ably regarded by him as beginning at the surface of the cell. He 
describes it as commencing by a "cording-in" of the surface of 
the yolk (which he seems to have viewed as a simple cell), and says 
that by the continuance of this process the yolk was divided into 
two equal parts, these two into four, these again into eight, and so 
on until the well-known "mulberry mass" was produced. In this 
account of cell growth the nucleus plays no part; it is not men- 
tioned in this connection by Henle, but the whole process is 
attributed to the cording-in, or furrowing, which, commencing at 
the periphery, was supposed to proceed towards the centre, until 
actual division took place. The language employed leads one to 
infer that the division was rather the result of a mechanical than a 
vital act; that the so-called "cording-in" was more a species of 
ligation or constriction than the outgrowth of any manifestation of 
vital force. Hence, Henle's theory must not be looked upon as at 
all equivalent to the later and more correct one of cell multiplica- 
tion by division or budding of pre-existing nuclei. Other ob- 
servers have admitted the possibility of cell growth independently 
of the nucleus: Paget, having met with morbid growths which 
were entirely destitute of nuclei, believed that new cells might 
arise without the aid of nuclei; Karsten stated, in 1843, iat ce^s 
arise from amorphous granules, without the presence of a nucleus, 
and added that " when the nucleus is present, the origin of cells is 
quite independent of it."* Gliige is equally clear upon this point. 
"The formation of a nucleus," writes he, "is not an essential 
condition to the production of cells, for there are instances in 
which the latter occur without having been preceded by a nucleus." 
But he adds that "all non-nucleated cells do not belong to this 
category, for frequently a nucleus originally exists, but afterwards 
becomes indistinct or disappears entirely by solution in the cell 
contents,"f an idea previously advanced by Von Baer in respect 
to the germinal vesicle (nucleus) of the impregnated egg, and quite 
recently concurred in by Stricker, so far as regards the germinal 
vesicle of the egg of the frog.| Briicke maintains that "no proof 
has been given that the nucleus is indispensable to our conception 
of a cell," and " rests his statement on the fact that cells are known 
to occur in the cryptogamia in which no nucleus is visible." "We 
* Tyson, of>. cit., p. 41 (note). 
f Gliige, Pathological Histology, p. 32. 
+ Stricker's Histology (Sydenham ed.), vol. i. p. 8. 1872.] 
The Cell. 
215 
have," he-says, "no positive information either respecting the 
origin or the function of the nucleus; even the constancy of its 
occurrence appears to be subject to certain limitations, especially 
if we consider the cells of cryptogams, and do not start with the 
presupposition that, even in those cases where no nucleus is visible, 
it must nevertheless be present;"* and Stricker adds that the 
"opinion of Briicke undoubtedly gains weight the more carefully 
the subject is considered." Comparatively recent discoveries, 
however, concerning the mode of propagation of the simplest 
forms of living beings, seem to confirm the supposition that, in 
certain exceptional cases, cells multiply themselves without the 
presence of a visible nucleus. Thus: "Max Schultze has dis- 
covered a non-nucleated Amoeba in the Adriatic Sea; E. Hackel 
a larger non-nucleated Protista {Protogenes primordialis}, which 
propagates by division, in the Mediterranean; and lastly, Cien- 
kowski has described two non-nucleated monads, namely, Monas 
amyli and Protomonas amyli." \ It follows from all this that cell 
multiplication, independently of the presence and agency of nuclei, 
must be regarded as an established fact, or we must believe that 
three very skillful as well as very conscientious histologists have 
permitted themselves to be grossly deceived. A very interesting 
practical question meets us here, which I must reserve for future 
consideration : namely, Is there any real difference between cell 
multiplication through the agency of, and independently of, what 
we are accustomed to call " nuclei"? 
(<7.) Theories which confine Developmental Power to the Nucleus 
alone.-Robert Brown discovered the nucleus, but he was not en- 
dowed with sufficient mental outreach or power of generalization to 
enable him to appreciate its importance ; that was reserved for the 
pioneer of the modern epoch in histology, namely, Schleiden. 
As I have already remarked, the name conferred upon the nucleus 
by Schleiden, namely, "cystoblast," or cell-bud, clearly indicated 
his notions as to its function. Precisely at this point does the 
student in histology first find himself upon a footing whereon he 
can firmly stand. The theory of Schleiden, which recognized the 
true function of the nucleus, has proved to be the corner-stone of 
our present histological fabric; nor ought it to lessen his merit in 
* Stricker, of>. cit., p. 8. 
f Stricker's Histology, loc. cit. 216 
The Cell. 
[Oct. 
our eyes that he had previously accepted the doctrine of free cell 
development. The term "cystoblast," if it could be separated 
from its derivative, " cystoblastema," which is only calculated to 
mislead and deceive, is the most appropriate name which has yet 
been bestowed upon the nucleus. It is as truly the or germ of 
the future cell as the rose-bud is the germ of the future rose. It 
as truly and no more truly performs the duties of the future cell 
than the rose-bud performs the duties of the future rose. Follow- 
ing the lead of Schleiden, later observers, whatever theories they 
may have advanced, have pretty generally recognized the develop- 
mental power of the nucleus. Thus, Schwann extended the doc- 
trines of Schleiden to animal tissues ; Goodsir regarded the nucleus 
as the "permanent source of successive broods of young cells;" 
Huxley, in 1853, says of the endoplast (nucleus), it "grows and 
divides; but, except in a few more or less doubtful cases, it would 
seem to undergo no other morphological change;" and Todd and 
Bowman endow the nucleus with the power of cell-multiplication. 
The language of Virchow concerning the function of the nucleus 
is well worth quoting, both on account of his direct and business- 
like way of stating his views, and the intrinsic weight which always 
attaches to his conclusions. After some preliminary observations 
upon the cell, he continues as follows: "You will hereafter be 
made acquainted with a series of facts in the history of pathologi- 
cal and physiological development, which render it in a high de- 
gree probable that the nucleus plays an extremely important part 
within the cell,-a part, I will here at once remark, less connected 
with the function and specific office of the cell than with its main- 
tenance and multiplication as a living part. The specific (in a 
narrower sense, animal) function is most distinctly manifested in 
MMtk***. nerves, and gland-cells; the peculiar actions of which- 
contraction, sensation, and secretion-appear to be connected in 
no direct manner with the nuclei. But that, whilst fulfilling all its 
functions, the element remains an element, that it is not annihi- 
lated nor destroyed by its continual activity, this seems essentially 
to depend upon the action of the nucleus. All those cellular forma- 
tions which lose their nucleus have a more transitory existence; 
they perish, they disappear, they die away, or break up."* And 
he adds, in almost the same breath, " We are acquainted with no 
part which grows or multiplies, either in a physiological or patho- 
* Cellular Pathology, p. 37. 1872.] 
The Cell. 
217 
logical manner, in which nucleated elements cannot invariably be 
demonstrated as the starting-points of the change, and in which 
the first decisive alterations which display themselves do not in- 
volve the nucleus itself, so that we can often determine, from its 
condition, what would possibly have become of the elements."* 
Virchow, therefore, repudiates all theories of cell development ex- 
cept that in which the nucleus is the developmental agent. 
To Prof. Lionel S. Beale, of London, the world is more indebted, 
it seems to me, than it has yet seen fit to acknowledge. Nor is 
this at all strange. Clad in an impenetrable garment of good stiff 
English egotism ; firmly convinced of the absolute correctness of 
his own views, and the absolute incorrectness of the views of every- 
body else; ready at all times to fancy himself "hit," and more 
than ready to strike back; the author of two or three very useful, 
and a far larger number of very useless, books; a writer of ordi- 
nary ability, but of extraordinary productiveness so far as pages of 
'octavo are concerned ; these qualities, either singly or combined, 
are not calculated to win the esteem or command the confidence 
of the great brotherhood of scientists. And yet Prof. Beale de- 
serves the highest commendation. He is an indefatigable worker; 
as a microscopist he has few equals, and probably no superiors, and 
he is largely endowed with that quality of persistency, which always 
means results. His cell theory is attractive and plausible, and, so 
far as the function of the nucleus is concerned, has been accepted 
by a considerable number of observers, and is likely to increase 
rather than diminish its adherents. The cell, as a whole, he calls 
the "elementary part;" the nucleus, "germinal matter" (more 
recently, "bioplast"); and all outside the nucleus, "formed ma- 
terial." The "formed material" is solely the product of the 
action of the "germinal matter;" through the agency of the 
formed material the various functions of the body are carried on ; 
and yet, by a strange paradox, this very formed material is, accord- 
ing to Dr. Beale, dead, or, to employ a softer phrase, " non-living." 
Just here we must for the present leave the formed material, with 
the purpose of returning to the subject on a future occasion. The 
"germinal matter" is the living portion of the cells; it is em- 
phatically alive,-a living mass ; it is endowed with the power of 
taking up " pabulum " and converting it into matter like itself; it 
possesses the power of infinite growth, and is constantly beset with 
* Op. cit., p. 38. 218 
The Flora of Chicago and Vicinity. 
[Oct. 
the desire to subdivide or cast off little buds or masses from itself, 
and these little masses, however minute they may be, possess all 
the properties and endowments of the parent mass; it is soft, 
transparent, colorless, and structureless; by an inherent power of 
movement it can change its form, and, within certain limits, exer- 
cise the function of locomotion. Germinal matter is distinguished 
from formed material by its capability of being deeply and perma- 
nently stained by an ammoniacal solution of carmine; whereas the 
formed material either takes no color or else a very much lighter 
tint than the germinal matter. Such, briefly, but I believe essen- 
tially and fairly, is the theory of Dr. Beale regarding the nucleus, 
"germinal matter," or "bioplasm." The term bioplasm was first 
brought into use by Dr. Beale, partly because it expressed precisely 
what he wished to express, and partly because that over-busy word, 
"protoplasm," was just then intensely occupied in trying to be 
all things to all men, and, therefore, no longer capable of associ- 
ating itself permanently with any one particular thing. 
It would not be difficult to multiply examples of theories re- 
lating to each mode of cell development, but those already adduced 
are sufficient for my present purpose. I have not attempted to 
write an exhaustive history of cell doctrines,-a work already so 
satisfactorily accomplished by Dr. James Tyson, of Philadelphia,- 
but rather to follow out certain trunk-lines of thought which have 
culminated in specific theories, or rather groups of theories. Our 
present notions concerning the cell are the outgrowth of a quarter 
of a century's labor. It is the successive steps in this growth that 
I am now endeavoring to trace. 
I. N. Danforth, M.D., 
Pathologist to St. Luke's Hospital. 
Chicago.