A THEORY OF HEREDITY. 



223 



to the succeeding generation the chromosomes of the two parents, but 

 the ph)'sical and chemical impossibility of the single cell containing all 

 the necessary determinants for all possible forms of life is readily per- 

 ceived. The germ plasm may be acted upon by enTironment, as would 

 be indicated by the effect of intoxicants (in a bro^d sense such intoxicants 

 as alcohol, bacterial toxins, internal secretions, diathesis, etc.), in the 

 hereditary transmission of tendencies and in producing monsters, epilep- 

 tics, etc. Therefore, the immortality and immutability of the germ 

 plasm must be acknowledged to be inconceivable. 



Adami's scheme, which is a combination of Bhrlich's side chain theory 

 and Mendelian heredity, is a good graphic representation of the chro- 

 matic relations of the germ cells. Bach germ cell has a central ring 



romosomes 



ChromosomS 



CentTosome 



pi a Sr 



Fig. 3. — Weissmann conceives that the chromosomes which produce an individual consist 

 of many ''ids" each of which contains all the possibilities of a new organism. The 

 "ids" possess an historic architecture that has been slowly elaborated during the 

 multitudinous series of generations that stretch backward in time from every living 

 individual. Each "id" consists of determinants which represent the various parts of 

 the individual that may undergo variation, and each determinant is composed of 

 biophores which enter the cells and direct their vital activity. 



with side chains to which are linked aifinities (fig. 4). The chromo- 



FiG. 4. — Adami considers that the germ cells are similar in nature to the benzene ring. 

 The chromosomes represent the side chains that link together affinities. Like chro- 

 mosomes attract like. Unlike chromosomes repel each other, but may finally fuse 

 after repeated contact through many generations. 



somes represent the side chains. The central ring does not alter, but 

 the side chains may. Sex cells or germ cells contain the original side 

 chain imaltered. Liver cells, muscle cells, etc., contain many side chains. 



