322 
NATURE 
[ Feb. 2, 1882 
year. In 1848 he migrated to the chair of Anatomy 
in the University of Liége, where he remained to the 
time of his death, having exchanged after a time, the 
chair of Anatomy for that of Physiology. It is note- 
worthy that Schwann was a Catholic, which probably had 
some influence in his selection by De Ram, the ecclesias- 
tical Rector of Louvain University, for the chair which 
he first occupied, and he appears to have retained the 
confidence of the Catholic hierarchy in the later years of 
his life, if we may judge by the fact that an attempt was 
made by the clergy to procure him as an expert witness 
in the case of the reputed miraculous ‘“‘stigmata” of 
Louise Latour. 
Only four years ago—the professors of Litge and the 
scientific men of Belgium organized a festival to celebrate 
Schwann’s fortieth year of professorship in his adopted 
country. From all parts of Europe addresses of con- 
gratulation flowed in, and public honours of all kinds 
were showered upon the head of “the founder of the 
Cell-theory.”. Schwann was naturally a man of retiring 
disposition, and simple habits of life. He had visited 
London twice within the last thirty years, and had not 
cared to make himself personally known to his colleagues 
there; he was equally unknown in the laboratories and 
scientific gatherings of his German fatherland. As he 
had published very little if anything since 1845,—though 
actively engaged in his professorial teaching at Litge 
which was very highly appreciated—Schwann had become 
to most biologists, one of the great names of the past 
—a revered historical character. To sit with him in 
front of a café in the pleasant streets of Louvain, and 
hear him discourse of the progress of histology and the 
germ-theory of disease some six years ago, was, for the 
present writer, a pleasure only less startling than that 
which could be conferred by one risen from the dead. 
His modesty did not prevent Schwann from keenly en- | 
joying the festival offered to him by his colleagues in 
1878 ; and for some time after that event, he was busy in 
arranging the pub'ication, for circulation among his friends, 
of a volume which contains an excellent photograph of 
himself and a complete report of the eulogistic speeches, 
and a reproduction of the hundred or more addresses 
from foreign universities and academies which the occa- 
sion of his festival called forth. 
Among the many honours which Schwann received in 
1878 or had previously acquired, may be mentioned the 
foreign memberships of the Royal Society of London, 
and of the Academy of Sciences of Vienna. and the 
Prussian cross ‘pour le mérite’; whilst as early as 1845 
he received from the Royal Society of London its most 
coveted decoration, the Copley medal. 
Three important pieces of work are due to Theodor 
Schwann, each of which was the starting point of endless 
researches carried out by his successors, and to each is 
stiil directly and clearly traceable a distinct and vastly 
important line of investigation which, up to the present 
day, is being pursued with ever increasing activity. The 
first of these consists in his observations and reflections 
relative to the cell-structure of organisms ; the second is 
his discovery of the organic nature of yeast, of the yeast 
plant as the cause of alcoholic fermentation, and of or- 
ganisms as the cause of putrefaction in general ; the third 
is his investigation of the laws of muscular contraction 
which is declared by the competent authority of Du Bois 
Reymond to have been “ the first occasion on which an 
eminently vital force was examined as a physical force, 
and the laws of its action expressed mathematically ia 
numbers.” 
Schwann’s name is very generally known only in con- 
nection with his “ microscopical researches into the ac- 
cordance in the structure and growth of animals and 
plants,’’ and as it seems to us somewhat erroneously, his 
merit is apt to be associated prominently or even exclu- 
sively with the history of Histology. In reality Schwann’s 
merit as an anatomical histologist is comparatively a 
minor affair ; the striking features in his Microscopical 
Researches are his breadth of view and the physiological 
generalizations which really constitute his cell-theory. 
Schwann started the conception of a physiology (7.2, a 
truly chemico-physical physiology) of the cell and without 
using the word “protoplasm” laid down in principle 
all that it implies. He established in so many words 
the difference between “crystalloids” and “ colloids,” 
and attributed the peculiar growth of cells to the capacity 
possessed by their substance of imbibing liquids; and 
further suggested that a peculiar molecular arrangement 
may exist in these colloid units comparable to the mole- 
cular structure of true crystals. 
Both in animals and in plants “cells” had been recog- 
nized asa very general feature of their structure, previously 
to 1838. Comparisons had been made between the “ cells” 
known to form plant-tissues and the “cells” seen in some 
animal tissues. Johannes Miiller had especially compared 
the cells of notochordal tissue to the cells of vegetable 
parenchyma and had led Schwann to give attention to 
this matter. But as yet there had been no notion that 
the cells of plants were the same kind of things as the 
cells discovered in animals. Mirbel followed by Schleiden 
now propounded the view that a// vegetable tissues are 
formed of cells more or less modified, and are produced 
by the developmental transformation of a primitive cellular 
tissue. This conception, as Schwann states, fired his 
imagination and the hypothesis occurred (in 1837) to him 
that animal and vegetable cells are of identical character, 
the structural and physiological units of organic nature, 
and that not only vegetable tissues but animal tissues also 
are ultimately to be traced to cells. He proceeded most 
laboriously to test his hypothesis by searching for cell- 
structure in every kind of animal tissue upon which he 
could bring his microscope to bear. He confirmed his 
hypothesis and not only that, but he made a number of 
important discoveries, in detail, as to the structure of 
animal tissues, and published his ‘ Researches” in 
1839. 
The merit of transferring the botanical doctrine of cell- 
structure to animals and of thus raising it from special to 
universal application, was undeniably a great one and 
belongs to Schwann, as does also the merit of having 
securely established this doctrine by new observations—a 
task which speculative naturalists are often, in similar 
cases, disposed to leave to the care of their disciples. 
But it is not this #zorphological generalization as to cell- 
structure which is Schwann’s greatest claim to our regard. 
That is to be found rather in his physiological cell-theory, 
in the masterly chapter in which he lays down the view 
that the physiological processes occurring in these units 
called cells are, when summed up, that which we call 
“life.”and that these processes may be traced to mechanical 
(that is to physico-chemical) cases. The later “ proto- 
plasm-theory” is scarcely an advance upon Schwann, as 
compared with the great gap which separates his “cellular 
physiology ’’ from all that preceded it.* 
? The following extracts from Schwann’s last chapter of his ‘‘ Researches,”” 
entitled “* The Theory of Cells,” cannot fail to interest and even astonish 
the reader when he reflects that they were written five-and-forty years ago, 
when the doctrine of evolution was almost if not entirely ignored by natura- 
lists. It is also instructive to note that the man who held these views and 
proclaimed them was an orthodox catholic, and was not considered unfit to 
be called from Berlin to a Belgian university by the clergy, nor subsequently 
did a Liberal Ministry fear to promote him from the Chair of Louvain to 
that of Liége. 
(a) ‘In physics all those suggestions which were suggested by a teleo- 
logical view of nature. such as ‘horror vacui,"”’ and the like, have long been 
discarded. But in animated nature, adaptation—individual adaptation—to 
a purpose, is $9 prominently marked, that it is difficult to reject all teleo- 
logical explanations. Meanwhile it must be remembered that such ex- 
planations which explain at once all and nothing, can be but the last 
resource, when no other view can possibly be adopted. In the case of 
organised bodies there is no such necessity for admitting the teleo 
logical view. The adaptation to a purpose which is characteristic of 
organised bodies differs only in degree from what is apparent alse in the 
inorganic part of nature; and the explanation that organised bodies are de- 
veloped, like all the phenomena of inorganic nature, by the operation of 
