ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 503 



as malic acid, which has four forms. " A fortiori, idioplasm may be 

 capable of an enormous number of modifications. The mode of the 

 atomic arrangement in the idioplasmic molecule may, therefore, in part, 

 explain the variation in the properties of that idioplasm seen through- 

 out the animal aud vegetable kingdoms." But it seems too much to 

 assume for each species, or even individual, a different atomic structure 

 of the idioplasm. Therefore the author pictures the primitive idio- 

 plasm as composed of a mass of material, each molecule of which is 

 formed of a central ring, to which there can be attached, side chains, 

 from which sundry side chains can be detached without the central ring 

 being destroyed. 



" It is not necessary to regard the molecules of idioplasm as at 

 all times presenting their completed structure, with every side chain 

 attached. On the contrary, we are free to conceive the molecules being 

 laid down and being transmitted in a relatively simple form, some of 

 the side chains only becoming attached when the molecules are brought 

 into certain particular relationships with their surroundings. It is not 

 necessary, for example, to hold that already in the ovum there is idio- 

 plasm identical in structure with that eventually present in the muscle- 

 fibres or nerve-cells developed from that ovum. Rather we must hold 

 that in the ovum there is one common idioplasm of simple type, to 

 which, when distributed in the various cells derived from that ovum, 

 different side chains become attached, according to the relationships 

 assumed by those cells ; so that the cells of different orders are con- 

 trolled and formed around protoplasmic or idioplasmic molecules com- 

 posed of these central rings plus varying series of side rings 



Indeed, idioplasm possessing its full complement of side chains must 

 be regarded as ipso facto incapable of initiating cell-multiplication." 

 [This suggestive theory seems in some respects a chemical re-statement 

 of the position of Driesch and Hertwig. The reader will recognise 

 that the idioplasmic molecule is quite as hypothetical as Weismann's 

 « ids."] 



Prof. Adami first illustrates his side-chain theory of inheritance by 

 reference to unicellular forms, where he finds " the simplest example of 

 the inheritance of acquired characters." [The difficulty of applying 

 the conception of an " acquired character " or " direct somatic modifica- 

 tion " to forms like bacteria has often been pointed out.] From the 

 importance of environmental influence in bacteriological work tbe 

 author works upwards to its importance, both in the development of 

 the body and in the slow alteration of the idioplasm in the germ-cells. 

 " Variation, whether slight and individual or extensive, and leading to 

 the production of species, is ultimately the expression of modification 

 in the constitution of the idioplasm brought about by environment." 

 [But Weismann has also said, "The primary cause of variation is 

 always the effect of external influences," and much more to the same 

 effect.] 



Passing to special medical problems, Adami admits the non-trans- 

 mission of acquired mutilations. "At most we can conceive the possi- 

 bility of indirect effect where the mutilation is extensive or affects 

 organs playing an important part in general nutrition." 



He next argues in support of " the indirect inheritance of acquired 

 diathesis." Constitutional disease may have an effect upon the germ- 



2 M 2 



