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written in the life history of the Protozoan and in the growth of 

 cells, in the tissues in the budding of the Metazoa and partheno- 

 genesis as in these more complicated forms, but the phenomena ot 

 transmission occurring after conjugation can be separated from 

 growth and considered upon entirely distinct lines. 



The theories offered show this. Thus the corpuscular theories, 

 whether gemmules or biophors or pangenes are assumed, assert the 

 need of minute bodies for the transmission of characters, while on 

 the other hand the dynamic theories, maintained principally by 

 American authors, are more in accord with physical phenomena in 

 assuming that there is a transmission of molecular energy, and some 

 of these views support Hering's theory of what may be called mne- 

 megenesis, 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 devel- 

 opmental results of growth and appears chiefly in the cytoplasmic 

 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 

 retrogression 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 phe- 

 nomena 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 distinct forms 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 tracing the genetic 

 relations of varieties and species of fossils Cephalopods and other 



KtyjZO^, something acquired. 



