3i8 Report S.A.A. /idv \ncemenj of Science. 



arrangemenls and mii;rati()ns nl' material particles as have been 

 imagined In Darwin and Weismann. 



It must not Ije supposed that 1 wcnild deny for a moment that 

 the inherited characters of an ori^anism are intimately associated in 

 some unknown way with certain material substances lodged in 

 certain of the cells of that organism. On the contrary, I believe, with 

 others, that these characters are associated with the chromosomes or 

 darkly staining bodies of the mu-leus. anfl that we may perhaps 

 regard these chromosomes as the seat of complex systems of forces 

 in somewhat the same way as storage batteries may be regarded as 

 reservoirs of electricity, although of course this analogy can easily 

 lie pushed loo far. Such an hyi)Othesis as this, however, is a very 

 different thing from the supposition that every ancestral character is 

 represented in the germ cell by a separate particle which must under- 

 go an elaborate series of subdivisions and migrations as the organism 

 developes in order ultimatelv to reach its particular sphere of 

 influence. 



Darwin, it is true, regards his iheor\ of pangenesis as a pro- 

 visional hypothesis. Init even supposing it to be valid so far as it goes, 

 still it does not bv anv means go to the root of the matter. Even if 

 his " gemmules " could be shewn to exist, still the theory does not 

 explain in the least how these gemmules came to control the develop- 

 ment ()( the particular cells with which they are believed to be 

 associated, and it is the nature of this control which we really want 

 to get at. The assumption of an immense numljer of material 

 [)articles each representing some somatic character, or group of 

 characters, does not really help us. .\s Herbert Spencer said long 

 since : " We find ourselves again Ijrought down to the persistence cf 

 force, as the deepest knowable cause of those modifications which 

 constitute physiological develo])ment : as it is the deejjest knowable 

 cause of all other evolution." 



Loeb also, in speaking of his wonderful researches upon fertiliza- 

 tion, has quite recently made a similar statement, that he consi<lers 

 " the chief value of the experiments on artificial parthenogenesis to be 

 the fact that they transfer the problem of fertilization from the realm 

 of morphology into the realm of physical chemistry." 



The principal exponent of the " Dynamic Theory ' of Heredity 

 is. however, the well-known American writer, Professor E. D. Cope, 

 and his views will l)e found set forth at length in his work on " The 

 Primary Factors of Organic Evolution." from which I take the follow- 

 ing qucjtation : — 



" The manner in which influences which have affected the 

 general structure are introduced into the germ-cells remains the most 

 difficult proljlem of biology. For its explanation we have nothing as 

 yet but hypotheses. The one which has seemed to me to be the 

 most reasonable belongs to the field of molecmlar physics, and it 

 must be long before it is either proved or dispnjved. I have termed 

 it a ' dynamic theory,' and it is in some resjjects similar to that sub- 

 sequently proposed by Haeckel under the name of the ' perigenesis 

 of the plastidule." I have alreadv referred to the phenomena of the 



