No. 533] NUCLEUS AND CYTOPLASM IN HEREDITY 



2s:> 



reactions where a number of associated substances are 

 concerned and where certain of the materials, before they 

 can become active, must await the outcome of the reac- 

 tions between other members of the mixture. For ex- 

 ample, when hydrochloric acid is passed into an alcoholic 

 solution of hydrocyanic acid, provided there are suffi- 

 cient quantities of these three ingredients, live definite 

 crystalline end-products of their interaction result. First 

 the hydrochloric and hydrocyanic acids combine to form 

 amido-formyl-chloride, which then adds another mole- 

 cule of hydrocyanic acid. This product next reacts with 

 one molecule of alcohol which to this point has been inac- 

 tive. The result is what we may call end-product one. 

 Then end-products two, three and four, respectively, are 

 formed by the successive additions of a single molecule 

 of alcohol to separate molecules of a part of the immedi- 

 ately preceding end-products. The fifth end-product is 

 not so directly related to the others. It is elaborated 

 chiefly through the interaction of hydrocyanic acid and 

 water, but this interaction can not take place until water 

 is released through dehydration of some of the other 

 compounds. There is little doubt that such sequential 

 reactions as these may be taken as simple models of what 

 goes on on a tremendous scale in the developing germ- 

 cell. 



It is a well-known chemical fact, moreover, that when 

 two or more progressive reactions are going on simul- 

 taneously, a quickening or retardation of the velocity of 

 either, with the consequent precocious development of 

 certain stages in the sequence, may lead to a partial or 

 complete deflection of the original trend of the reactions 

 and the formation of entirely different end-products than 

 would otherwise have resulted. And velocities may be 

 varied greatly by such factors as temperature and cata- 



this, the substance of the germ-cell, in so far as we know 

 !t, is of materials such as proteins, carbohydrates and 

 fats which we have no reason for doubting are subject 



