lotsy's theory of evolutlon. 26 r 



and other autocatalytical substances, in thus choosing" tliem to create a 

 system of structural relations, and thus a "body" for the comljination. * 



He points out that one can, e.g., separate by filtration the 

 active substance of the tetanus bacillus and of the yeast plant, 

 and that these essential parts of the bacteria and yeast celk 

 are combined in these organisms by surface-tensions and other 

 forces to form the specific organism, while through pressing 

 they have lost this form. I am afraid I cannot follow this 

 reasoning. If I remove the motorcars from a motorcar factory, 

 I get some idea of its activity ; but without having seen such a 

 factory I have no idea how the building and the machinery it 

 contains are constructed, and how a motorcar is manufactured, 

 and no amount of motorcars put together will make a motorcar 

 factory ; and the same applies if in the same factory other 

 vehicles or tools are also made. In other words, the substances 

 produced by cells do not give us any idea of the ultimate struc- 

 ture of their vital parts, the protoplasm; and while one may 

 even admit that the metabolic activities of protoplasm are 

 carried on largely by catalytical substances, this does not mean 

 that we have any insight into the structure of protoplasm which 

 manufactures them, and how, e.g., it can react to stimuli, how 

 the protoplasm of dift'erent parts of the same organism reacts 

 in opposite directions to the same stimulus, how it can change 

 its reactions, and so on. 



Lotsy, believing in the constancy of homozygotes, naturally 

 asked the question how this belief can be harmonised with a 

 belief in the evolution of species. The answer is, according to 

 him, as mentioned above, indicated in crossing of different 

 Linnean species of Antirrhiiiuin. He showed with Baur that 

 these possess segregating Mendelian characters which hitherto 

 were supposed to be restricted to varieties, and by crossing these, 

 there arise, sooner or later, sometimes in Fo, some homozygote 

 combinations, thereore iieic sj^ecies. It seems to me, however, 

 doubtful whether — , 



(i) The i-esult of his experiments can only bear the inter- 

 pretation which he ascribed to it ; 



(2) They can prove that species may not arise by other 

 methods. 



In view of ^Mendelian segregation and comliination of 

 characters, it is generally assumed that the chromosomes during 

 mitosis bear definite hereditary tendencies. 1liis may be con- 

 ceded ; but when these tendencies are pictured as something 

 tangible, something which is. as it were, bodilv included in the 

 nuclear substance — something that, if our methods were refined 

 enough, could be separated and perha])S iniected into other 

 organisms with the result of giving them additional properties, 

 then I cannot accept the view. We know {e.g.. in Polysiplioiiis, 

 dicfyota) that haploid individuals may have the same external 



* As quoted by Lotsy, p. 386. 



