Hyatt.] 82 [Aprils. 
organism wliicli is ineradicable and lead to the foundation of 
liereditary differentials and the arising of new stocks may well be 
doubted, since there is no adequate proof of this position. In 
fact it may be said that what little is positively known in this 
direction is opposed to Weismann's theory. 
Thus Hatschek entertains the opinion, founded ujion Galton's 
observation, that the mingling of the sexes practically tends, as 
do all the manifestations of genetic forces, to hold the organism 
true to the normal or typical form of the species or breed. 
Minot in his masterly work ''Human embryology," agrees with 
Hatschek and states that he is inclined to maintain with him 
that reproduction is apt to correct variations and so preserve the 
specific type. In fact, one can hardly admit without positive 
proofs that characteristics derived from jjurely hereditary sources 
can be variations in the same sense and having the same influ- 
ence in founding new forms as those that arise from the action of 
other and less conservative influences. 
Cope and ])erhaps all of the supporters of dynamical theories of 
genesiology in this country have opposed these opinions more or 
less. The entire nature of genism, so far as it is known, tends to 
hold back an evolving line of characteristics or forms from vari- 
ation or departure in new directions, and in the old of the indi- 
vidual and in the decline of a type may even force the organism to 
repeat more or less the purely morphic characters of the younger 
ancestral forms after the suppression of the variations acquired 
in the intermediate periods of development and evolution.^ 
Thus the study of the relations of the cycle is directly opposed 
to Hurst's views that variations preceded heredity and that the 
latter arose out of the inevitable repetitions of variations. If tlie 
nature of genism has been approximately defined above, it is the 
repetition of similarities which is apt to take place. The repeti- 
tion of variations dejDends upon their duration and fixation in the 
organism for a sufficient time, so that they become incorporated 
similarities and can be taken up and carried forward into other 
forms by genism. Genesiology, therefore, to sum up the matter 
in a few words, deals with the problems of the perpetuation of 
forms and characters, whe'ther arising through growth by fission 
or through the conjugation of two organisms. 
' See remarks upon "Bioplastnlony'' and ''The cycle." 
