HOMOLOGY AND ITS INTERPRETATION 57 



upon which to account for the existence of these inorganic 

 uniformities. Here analogous chemical constitution, produced 

 in accordance with a general law, results in uniformity that 

 implies a similar, rather than an identical, cause. The hy- 

 pothesis of parallelistic derivation from similar independent 

 origins accounts quite as well for the observ^ed uniformities 

 as does the hypothesis of divergent derivation from a single 

 common origin. Why, then, should we lean so heavily on the 

 already overtaxed principle of inheritance, when parallelism is 

 as much a possibility in the organic world as it is an actuality 

 in the inorganic world° 



As to the contrast here drawn between inheritance and other 

 similifying factors, it is hardly necessary to remark that we 

 are speaking of inheritance as defined in terms of Mendelian 

 experiment and cytological observation. In the so-called 

 chemical theory of inheritance, the distinction would be mean- 

 ingless and the contrast would not exist. Ehrlich's disciple, 

 Adami, sets aside all self-propagating germinal determinants, 

 like the chromomeres, in favor of a hypothetical "biophoric 

 molecule," which is to be conceived as a benzine-like ring 

 bristling with sidechains. Around this determining core the 

 future organism is built up in definite specificity, as an 

 arch is constructed about a template. Adami has merely ap- 

 plied Paul Ehrlich's ideas concerning metabolism and immunity 

 to the question of heredity, commandeering for this purpose the 

 latter's entire toolkit of receptors, haptophores, amboceptors, 

 etc., as though this grotesque paraphernalia of crude and 

 clumsy mechanical symbols (which look for all the world like 

 the wrenches of a machinist, or the lifters used by the cook 

 to remove hot lids from the kitchen range) could throw any 

 valuable light whatsoever on the exceedingly complex, and 

 manifestly vital, phenomenon of inheritance. It does not even 

 deserve to be called a chemical theory, for, as Starling cor- 

 rectly remarks concerning Ehrlich's conception, "though chemi- 

 cal in form," it is not so in reality, because "it does not explain 

 the phenomenon by reference tc the known laws of chemistry." 



