DeEcEMBER 17, 1896] 
NATURE 
147 
A NEW WORK ON CYTOLOGY. 
Die Morphologie u. Physiologie des Pflanzlichen Zell- 
kernes. Eine kritische Litteraturstudie. Von Prof. 
Dr. A. Zimmermann. Pp. 188. (Jena: Gustav Fischer, 
1896.) 
ft it be true that the growth of a science is to be 
estimated by the degree of division of labour which 
it exhibits, botanists have every reason to regard the 
work of the last fifteen years with no small degree of 
satisfaction. For. the incessant investigations in every 
department of plant-life have been so vigorously pro- 
secuted, that it has become utterly impossible for any 
simple mind to grasp the details of the various ramifi- 
cations of the subject as it exists at the present day. At 
the same time, it is essential for any one who desires to 
avoid the evil results of exclusive deyotion to one branch 
of the science, that he shall be in a position to appreciate 
the general nature of the results which are being arrived 
at in other fields of inquiry. 
Now it can hardly be denied that at present the 
why and the wherefore of the phenomena exhibited by 
living bodies is the theme which is attracting, perhaps, 
the widest share of interest on the part of the botanist and 
zoologist alike; and the generalisations accruing from 
investigations of matters germane to these problems, 
possess a significance hardly less weighty for others who, 
though not strictly speaking biologists, are yet seeking 
to penetrate the mysteries embodied in the terms life and 
organisation. 
And although we are accustomed to hear hypotheses 
confidently advanced and views dogmatically urged in 
connection with these and kindred matters, it is sur- 
prising to discover how small a substratum of solid fact 
we have as yet secured wherewith to lay the foundations 
for our many and elaborate theories. Thus the philo- 
sopher speculates on the origin and nature of conscious- 
ness, too often without possessing the faintest conception 
of the anatomy and physiology of the brain ; writers 
on heredity are too prone to generalise from a scanty 
range of empirical facts, the mutual relations of which 
are still at best but obscure. And yet it is only by 
carefully collecting and collating the facts, that they 
can be made to tell their own story; and seeing 
that the aims both of biology and of philosophy are 
at bottom the same, namely to explain as far as may 
be the phenomena of life, it is surely not too much to 
expect that the living substance, the protoplasm, should 
form a prime object of earnest research. We are 
fairly well acquainted with the rough and ready ways 
in which organisms adapt themselves to their sur- 
roundings ; we possess some knowledge as to the 
chemical processes which are inseparably associated 
with the exercise of vital activity ; but of the mechanism 
itself, of the essential machinery, we know next to nothing 
at all, and the isolated facts which have as yet been gleaned 
respecting it often appear so conflicting that we might 
almost despair of ever getting really at close quarters 
with the object of our quest at all. 
It is in the hope that this point of attack may prove 
to be not altogether impregnable, that such considerable 
efforts are being now concentrated on the details of cell 
structure. And we have made certain advances in this 
NO. 1416, VOL. 55] 
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| direction. 
We know that the essential feature of the 
| sexual process lies in the fusion of two cells ; we know 
that these cells have passed through antecedent changes 
very dissimilar from those which characterised the 
ordinary cells constituting the body or soma of the 
organism. What as yet we do zo? know is how to arrange 
our newly acquired facts in proper perspective; that 
knowledge can only be attained when our range of avail- 
able fact is far greater than is at present the case. But 
the obstacles which beset the investigator in this 
difficult path are so many, that it may even take years 
to unravel the sequence of events in a single nuclear 
division. Nevertheless it is certain that the time so 
spent 1s not wasted, for it is only when we shall have 
arrived at such a position as will enable us to compare a 
large number of carefully and accurately ascertained 
facts that we can reasonably expect to apply our know- 
ledge to the effective storming of some, at least, of the 
outworks of the citadel in which nature’s secrets are so 
jealously guarded. 
Dr. Zimmermann has rendered no small service to 
those who desire to do something in the field of cyto- 
logical inquiry. He has carefully and impartially 
(perhaps too impartially) summarised the results of 
nearly all the recent advances in this branch of botany, 
and thus his book forms a handy work of reference to 
the extensive literature which is so rapidly growing up 
on these matters. 
But the reader must not expect to meet with a 
critical and synthetic discussion of the results which 
have been obtained. He is left, for the most part, to form 
his own conclusions as best he can ; and perhaps we may 
be pardoned for wishing that Prof. Zimmermann had seen 
his way to give a little more definite expression to his 
own views, especially as he is himself well known as an 
investigator in these matters. For example, on page 59 
there is figured a dividing nucleus of Z/éwm Martagon, 
after Guignard, in which prominent centrospheres are 
represented as occupying the poles of the spindle. But 
in all the figures of the same plant taken from the 
author’s own works, the centrospheres are omitted ; and 
yet in one passage only (so far as we have seen) is any 
doubt tentatively cast on the accuracy of the statements 
alleging the existence of centrospheres in the lily. We 
think definite plain statements in a case like this would 
have been more useful than a cautious expression of 
doubts which have been growing up for a long time 
respecting the instance just cited. At any rate, such a 
course would have raised the question. It must be faced 
sooner or later, and the sooner it is raised—and finally 
answered—the better. 
The book is divided into three main parts, the first 
dealing with technique, and with the chemistry and 
physiology of the nucleus in general. The second part 
of the work is devoted to a consideration of the structure 
and behaviour of this body in the different groups of the 
vegetable kingdom, and a good deal of useful information 
respecting fertilisation and embryology is here brought 
together. The third part consists of a copious and most 
useful bibliography, which will be welcome to every one 
who wishes to obtain a more thorough knowledge of the 
subject. 
Dr. Zimmermann naturally could not profitably discuss 
