201 
Review. 
and small but perfect embryos may be produced. If on the other 
hand, the vivisection is a little deferred, till further stages of 
segmentation are reached imperfect embryos may result, the lost parts 
may or may not be replaced by regenerative processes that go on side 
by side, but not pari passu , with the progressive development of the 
mutilated embryo. The raw material for embryo formation may be all 
there, or at least be available, but the mechanism has been partly 
interfered with and its original co-ordination temporarily put in 
abeyance. Still more clearly is the same influence expressed in 
those numerous cases in which the structural parts of the young 
embryo are found to be correlated with the existence of specifically 
distinct zones or regions perceptible in the cytoplasm of the egg, 
any serious diminunition of which results, on fertilisation, in the 
growth of defective larvae as is shown in the sea-urchin at an early 
period of its development, or in Beroe in the most adult stage. Other 
facts further pointing to the supreme importance of the egg 
regarded as a whole, as opposed to that of the individual blasto- 
meres, when cleavage is artificially modified, all seem to point in 
the same direction. But nevertheless the form , that expression of 
the forces residing in and acting upon the material of which the 
labile mass is composed, is often ultimately and completely restored ; 
and when it is not, or when some new character (malformation or 
abortion) appears instead, this may be regarded as an indication 
that the serial changes that have gone on in the mass have induced 
a more or less profound change in the relations of mechanism and 
stimuli—probably both may be affected. 
(To be concluded.) 
REVIEW. 
THE MORPHOLOGY OP ANGIOSPERMS. 
T H E scope of the book under review 1 is more easily appreciated than 
defined. The reader sees at once that it makes noattemptto 
cover the whole subject suggested by its title. It is a fair-sized octavo 
of 358 pages,and from these must be deducted about 70 which are most 
1 .Morphology of Angiospenns(Morphology of Spermatophytes, 
Part II.), by John Merle Coulter, Pli D., Head of Depart¬ 
ment of Botany, the University of Chicago, and Charles 
James Chamberlain, Pli.D., Instructor in Botany, the Uni¬ 
versity of Chicago. Pp. X and 348. New York. D. Appleton 
and Company, 1903. 
