1 80 Oscar Riddle 



observation, as inheritance phenomena? The reason is that in- 

 quiry and reflection seem to attest that this behavior of aniline 

 dye is not an isolated thing in nature but that certain behaviors 

 are known which are universally treated as "hereditary," and 

 which rest upon essentially the same base. There is then, a group 

 of cases which exhibit the smiplest known inheritance phenomena, 

 and which may be considered in the light of, and be largely ex- 

 plained by our experience with Sudan. 



At the outset we call attention to the simplest analogy: the 

 fact that the entire fat content of the egg yolk, which in the egg 

 of a fowl aggregates several grams, is without doubt transmitted 

 from the soma to the egg in the same way that Sudan is trans- 

 mitted. That is to say, the fatty acids, which are re-s vUthesized 

 into fat within the yolk pass from the soma (i. e., from within the 

 body fluids) through the follicular membrane as these same fatty 

 acids; the fatty acid constitutents of the egg-yolk by no means 

 originating iu///z/?z the egg. This conclusion follows as a logical 

 necessity from our knowledge of fat metabolism elsewhere in the 

 body, as well as from the special findmgs of Henriques and Hansen 

 (03), who report the recovery of the specific and foreign fats of the 

 food from the egg-yolk of the fowl. Moreover, from the stand- 

 point of our general knowledge of metabolism it is not to be ex- 

 pected that these constitutents of the egg-volk should reach the 

 latter in^any other form. The protem of the egg-yolk, must also 

 be conceived as havmg entered the egg, or at least to have ap- 

 proached it, in a simpler form than protein, namely, as amino 

 acids, etc.; the reconstruction of these doubtless occur chiefly 

 within the egg itself and in this way give rise to the complex and 

 special proteins of the egg. 



These things which occur in the formation of every egg, these 

 "transmissions" of amino and fatty acids from soma to germ, 

 are cited because some biologists have considered the passage of 

 a molecule of dye, (azo-benzene "azo" 9 naphthol) from soma to 

 germ, a thing not at all to be expected. Perhaps this state of 

 thought is but an echo of the thoroughness of our long instruction 

 on the wide gulf supposed to separate germ plasm and somato- 

 plasm; on an implied immunity proceeding from follicular 

 walls, and an inviolate incorruptibility thought to preside over 



