152 BOTANICAL GAZETTE [FEBRUARY 
ment. Supposing that the bioplasm of the egg passes through stages a, 4, ¢, 
owing to the nature of the processes of assimilation of the biomolecules, bio- 
mores, etc., it is clear, the author states, that the first division of the egg cell 
be something different. ‘There are no other possible suppositions.” The 
author examines the second alternative, “polyodic development,” first, and 
arrives at the conclusion that this leads to an absurdity; hence the egg @ 
must divide into 6 and c; 6 must divide into c and dad, c into d and e, and so 
on to a particular limit fixed by the constitution of the egg. This is the 
principle of monodic development. : 
It would take us too long to follow the author's exposition of how this 
principle leads to a “rational” explanation of the development of all animals 
and plants, leaving no essential phenomena unexplained ; and, moreover, it 
is not necessary to do so for already two things must be clear: (1) that the 
Some of the main features of this system remind one of certain theories” 
of Weismann, e. g., the theory that protoplasm is a symbiotic aggregation of 
various orders of living units. But Weismann is far too good a biologist to- 
endow the molecules themselves with life. The principle of “‘heterogenetic 
artificial than that of Weismann, and he tries to solve by force of a priori 
reasoning what Weismann is careful to consider on the evidence. In many 
respects the theory departs widely from Weismann’s. 
he book contains no new facts, though the author is evidently familiar 
with some of the current embryological literature; but he makes use of the 
knowledge only to show that his theory is capable of explaining all of the 
results of experimental embryology. With other results of recent embryo- 
even probable that it will not be considered superfluous in the future to work 
for the discovery of new facts in ontogeny,— FRANK R. LILLIE. 
