320 
need of minute bodies for the transmission of characters, while on the 
other hand the dynamic theories, more in accord with physical phe- 
nomena assume that there is a transmission of molecular energy 
through growth and some of these views support Hering’s theory of 
what may be called mnemegenesis. Namely, that heredity is a form 
of unconscious organic memory and this from my point of view is the 
only satisfactory one yet brought forward. 
Heredity is obviously manifested for the most part in the deve- 
lopmental results of growth and appears chiefly in the cytoplasmie 
structures which Dr. Minot so clearly places before us as constantly 
increasing with age while the comparative size of the nucleus which. 
represents the power of growth force decreases. Whether this be 
granted or not, it can hardly be denied, that, in describing the de- 
velopment of organisms along ontogenetic and their evolution along 
phylogenetic lines we are dealing with cycles of progression and re- 
trogression which are quite distinct from the growth of the body as 
determined by the laws that govern its increase and reduction in bulk 
and that one cannot describe the study of both series of phenomena 
under the same general term without danger of confusion. 
Genism, in brief, is the transmission of likeness from one onto- 
genic cycle to another of the same species. It appears to be due to 
the same factors as the perpetuation and rejuvenescence of the cycles 
themselves, namely, the union of two forms of distinet ontogenic 
cycles of the same species or kind. 
Ctetology* 
Weismann and his supporters deny that ctetetic or acquired 
characters are inheritable, but it is safe to make the assertion that this 
will not be maintained by the students of Bioplastology. Within the 
limits of my own experience in placing the genetic relations of varie- 
ties and species of fossils Cephalopods and other groups through geo- 
logic time, although I have tried to analyze the behavior of all kinds 
of characteristics, I have failed to find any such distinctions. If 
Weismann’s theory is true it ought to be practicable to isolate in 
each type some class or classes of modifications that would be distin- 
guishable by the fact that they were not inherited. 
The only known cause of modification as demonstrated by the 
suitability of variations in existing characteristics, and by the more 
direct demonstration of experimentation , is the physical forces of the 
surroundings. ‘These certainly have the power to originate modifi- 
4 Krytdc, something acquired. 
