THE GERM-PLASM THEORY 



one received the < red/ the other tin- Mack ' determinante. Our , 

 can perceive no difference between tin- nuclear substance of the 

 cells, but the same is true of the chromosomes of the paternal and 

 maternal nuclei in the fertilized ovum, although we know in this 

 case that they contain different tendencies. In any ,-,■ qo 1 



justified in concluding from the apparent Bimilarity of the chromo- 

 some-halves in nuclear division thai there cannot be differentia] 

 division. The theoretical possibility that there La such differentia] 

 division cannot be disputed; indeed, lam inclined to say that it 

 is more easily imagined than the division of the ids into absolutely 

 similar halves. Both are only conceivable on the assumption thai 

 there are forces which control the mutual position of the determinants 

 in the ids, that is, on the assumption of ' affinities.' 1 shall nol folio* 

 this further, but that there are forces operative within the ids which 

 are still entirely unknown to us is proved at every nuclear division 

 by the spontaneous splitting of the chromosomes. 



It has been objected to my theory that such a complex whole as 

 the id could not in any case multiply by division, sine- there Lb 

 no apparatus present which can, in the division into two daughter- 

 units, re-establish the architecture disturbed by the growth. Bui 

 this objection is only valid if we refuse to admit the combining 

 forces, the * vital affinities' within the ids, and the same is true for 

 the smaller vital units. An ordinary chemical molecule cannot 

 increase by division; if it be forcibly divided it falls into different 

 molecules altogether; it is only the living molecule, that Lb, the 

 biophor, which possesses this marvellous property of growth and 

 division into two halves similar to itself and to the ancestral mole- 

 cule, and we may argue from this that in the division of the ids 

 forces of attraction and repulsion must likewise 1"' operative l . 



I see no reason why we should not assume the existence of Buch 

 forces, when we make the assumption that the hundreds of atomn 

 which, according to our modern conceptions, compose tie- molecule 

 albumen and determine its nature, are kept by affinities in tlii- 

 definite and exceedingly complex arrangement. ( »r must we supp 

 that between the atom-complex of the molecule and tie- next higher 

 atom-complex of the biophor, determinant, and id there is an absolute 

 line of demarcation, so that we must assume quite different fo] 

 the latter from those we conceive of as operative in tli<- former The 



1 In my book The Germ-Plasm I have already assumed the exist* 

 attraction ' in the determinants and biophors, as in the cells. I did not, ind- -1 • 

 into details, but I argued on the same basis as imw Germ-Ham . p. 64, English edition . 

 My critics have overlooked this. 



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