Hyatt.] 08 [Aprils. 
equally absurd. T. J. Parker says^ '•Heredity ... is nioilified 
by Variabilty' and earlier writers are not less slip-shod in their 
treatment of these and allied subjects." 
Clearness demands that some other term than heredity should 
be used and I consequently propose to designate the study of the 
phenomena by the term Genesiology from y«'v€o-is, meaning that 
which is derived from birth or descent. This force itself is a 
genetic force, and the principle of heredity thus becomes genism. 
Hurst's papers, although they treat the history of genesiology 
as if Haeckel, Darwin, and Weismann were the only authors 
worthy of quotation, are extremely suggestive and the facts of 
paleontology are in accord with some of his theoretical assump- 
tions. The neglect of paleontology has weakened his arguments 
as it has the various similar essays founded exclusively^ upon the 
observation of existing organisms. One can agree with his con- 
clusions that "heredity is merely a likeness of effects due to the 
likeness of the causes producing them" and that "heredity is 
essentiall}^ a limitation of variation" and also "that if no such 
phenomenon as heredity occurred in early stages of evolution 
it would of necessit}^ arise by degrees through the action of 
well-known influences, and without the intervention of any 
unknown force or gemmule," and yet be perfectly consistent in 
regarding heredity as the exhibition of a different process from 
growth and of a different although probably secondary form of 
growth force, as it is very commonly supposed to be at the 
present time. 
Mr. Hurst does not seem to have given full weight to the 
process of conjugation and consequent rejuvenescence which 
does not occur except through the union of distinct autotemuons 
and zoons and could not occur if this process was not very 
different from all others that produce an increase of mass. He 
also neglects noticing that in the case of asexual generation by 
fission the end is the establishment of new centers of assimilation 
and storage of energy. In the latter case the occurrence of like- 
ness is inevitable and not so far removed from the division of a 
homogeneous substance that we need feel puzzled that one pro- 
tozoon or cell generated by. fission is like its twin companion and 
must pass through similar stages of growth. 
» "Elementary Biology," 1891, p. 145. 
