Aprit 8, 1897 | 
NATURE 
On 
31 
which Prof. Wilson has given us has taken a form 
which, while it can hardly longer be described as 
“popular,” will be admitted by the more strictly scientific 
audience, to which it is now better adapted, to be in the 
highest degree fascinating. The advances which cellular 
biology has made, and is making at the present moment, 
can only be described as “leaps and bounds,” and to no 
part of the study of the cell will this apply with greater 
force than to that dealing with cell-propagation. A 
question which seemed to our fathers, and for the matter 
of that to some of ourselves not so very many years ago, 
as of the simplest nature and capable of being described 
in half a dozen lines, can no longer be adequately dealt 
with except in a volume devoted exclusively to it, and by 
men who make its study the business of their lives. 
And although works in other languages upon the subject, 
such as those of O. Hertwig and Henneguy, are available 
for the student, it is none the less a matter for congratu- 
lation that Prof. Wilson has given us in our own speech 
a work which is second to none in the clear and com- 
prehensive manner in which the facts of cell-structure 
and division are set forth, and the masterly way in which 
the principal theories which have been foundéd upon 
these facts are stated and criticised. Not the least 
striking feature of the book is the lavish way in which it 
is illustrated—a prime necessity in a work of this kind if 
it is to be easily read and understood. At the same time 
it is clear that the illustrations are carefully selected in 
each case with the object of presenting either a special 
fact or idea. And although, as might be expected from 
his position as a zoologist, Prof. Wilson has for the most 
part relied upon material furnished by the animal 
kingdom in illustration of his subject, he has not hesitated 
when occasion has offered to draw upon the important 
series of observations which have accumulated of late 
years in vegetable cytology. 
The subjects dealt with are, in the first place, the 
general structure of the cell, the phenomena of cell- 
division, the special structure of germ-cells (ova and 
spermatozoa), together with the parts played by’ the 
several cell-structures in the process of fertilisation, the 
formation of germ-cells and reduction of their chromo- 
somes. These subjects occupy some two-thirds of the 
entire book. Much of the remaining third is occupied 
by an interesting discussion on the nature and probable 
function or meaning of the several organised constituents 
of the cell ; including, besides the nucleus and its various 
parts, the centrosome and the so-called archoplasmic 
’ structures, ze, the asters and spindle and attraction- 
spheres. Their chemical relations and their physiological 
relations to one another are next passed in review. 
and, lastly, the most abstruse part of the subject—that, 
namely, which concerns the relation of cell-division to 
development and inheritance—is dealt with. The able 
manner in which Prof. Wilson has succeeded in over- 
coming’ the difficulty of presenting the various modern 
theories of inheritance, which are associated with the 
names of His, Nageli, Darwin, Roux, de Vries, Weis- 
mann and Hertwig, in a comparatively limited space, 
and with admirable clearness, can only be appreciated 
by those who have followed the long and apparently 
interminable manner in which these theories have, like 
the Pharaoh’s serpents which were popular some years 
NO 1432. VOL. 55] 
ago gradually extended their voluminous coils from a 
small and apparently inert mass of material, until a 
theory is ultimately evolved, which, in Prof. Wilson’s 
language, “demands for the orderly distribution of the 
elements of the germ-plasm a pre-arrayed system of 
forces of absolutely inconceivable complexity.” ‘ What 
lies beyond our reach at present, as Driesch has very 
ably urged, is to explain the orderly rhythm of develop- 
ment—the coordinating power th guides development 
to its predestined end.” “The same difficulty confronts 
us under any theory we can frame.” ‘The controversy 
between preformation and epigenesis has now arrived 
at a stage when it has little meaning apart from the 
general problem of physical causality. What we know 
is that a specific kind of living substance, derived from 
the parent, tends to run through a specific cycle of 
changes during which it transforms itself into a body 
like that of which it formed a part.” “ But, despite all 
our theories, we no more know how the properties of 
the idioplasm involve the properties of the adult body 
than we know how the properties of hydrogen and 
oxygen involve those of water.” “ We cannot close our 
eyes to two facts: first, that we are utterly ignorant of 
the manner in which the idioplasm of the germ-cell can 
so respond to the play of physical forces upon it as to 
call forth an adaptive variation ; and second, that the 
study of the cell has on the whole seemed to widen 
rather than to narrow the enormous gap that separates 
even the lowest forms of life: from the inorganic world.” 
A statement of fact which we must all have recognised, 
although few of us ever venture to assert it so boldly as 
Prof. Wilson has here done. 
A characteristic feature of the book is a glossary in 
which obsolete terms are distinguished from those still 
in use, and in which also are mentioned the name of the 
author first using the word, and the date of its employ- 
ment. This and a sufficiently comprehensive, but not 
too voluminous, bibliography will greatly add to the 
general usefulness of this admirable work. 
E. A. SCHAFER. 
PRACTICGAE PAHYSIES: 
An Intermediate Course of Practical Physics. By 
Arthur Schuster, Ph.D., F.R.S., Langworthy Pro- 
fessor of Physics, &c., Owens College, Manchester, 
and Charles H. Lees, D.Sc., Senior Assistant Lecturer 
and Demonstrator in Physics in the Owens College, 
Manchester. Pp. xv +248. (London: Macmillan 
and Co., Ltd. New York: The Macmillan Co., 1896.) 
LL who are engaged in the teaching of physics, and 
A all who are interested in scientific education, will 
take up this “‘ Intermediate Course” with the certainty of 
finding much in it that is helpful and suggestive, and they 
will not be disappointed. It fills a distinct place of its own, 
between the elementary text-books of practical physics 
and the more advanced manuals. Tosome, the fact that 
it has been primarily written with a view to a particular 
examination, may be a stumbling-block ; but, on close 
examination, there will be found in it nothing that can 
be fairly considered as “cram.” The authors are for- 
tunate in having had the very best help in drawing it 
up, namely, the criticism of successive generations of 
