(578 APPENDIX B. 



one of the co-operative parts may be fatal, as the sprain of an 

 over-taxed muscle shows us, I alleged that the chances are infinity 

 to one against the needful variations taking place at the same 

 time. Divested of its elaboration, its abstract words and tech- 

 nical phrases, the outcome of Professor Weismann's explanation 

 is that he accepts this, and asserts that the infinitely improbable 

 thing takes place ! 



Either his argument is a disguised admission of the inheritable- 

 ness of acquired characters (the effects of " intra-selection ") or 

 else it is, as before, the assumption of a fortuitous concourse of 

 favourable variations in the determinants " a fortuitous con- 

 course of atoms." 



Leaving here this main issue, I return now to that collateral 

 issue named on a preceding page as being postponed whether 

 the neuters among social insects result from specially modified 

 germ-plasms or whether they result from the treatment received 

 during their larval stages. 



For the substantiation of his doctrine Professor Weismann is 

 obliged to adopt the first of these alternatives ; and in his 

 Romanes Lecture he found it needful to deal with the evidence 

 I brought in support of the second alternative. He says that 

 " poor feeding is not the causa efficients of sterility among bees, 

 but is merely the stimulus which not only results in the formation 

 of rudimentary ovaries, but at the same time calls forth all the other 

 distinctive characters of the workers " (pp. 29-30) ; and he says 

 this although he has in preceding lines admitted that it is " true 

 of all animals that they reproduce only feebly or not at all when 

 badly and insufficiently nourished : " a known cause being thus 

 displaced by a supposed cause. But Professor Weismann pro- 

 ceeds to justify his interpretation by experimentally-obtained 

 evidence. 



He " reared large numbers of the eggs of a female blow-fly " ; 

 the larvaB of some he fed abundantly, but the larvae of others 

 sparingly ; and eventually he obtained from the one set flies of 

 full size, and from the other small flies. Nevertheless the small 

 flies were fertile, as well as the others. Here, then, was proof 

 that innutrition had not produced infertility ; and he contends 

 that therefore among the neuter social insects, infertility has not 

 resulted from innutrition. The argument seems strong, and to 

 many will appear conclusive ; but there are two differences which 

 entirely vitiate the comparison Professor Weismann institutes. 



One of them has been pointed out by Mr. Cunningham. In 

 the case of the blow-fly the food supplied to the larvae though 

 different in quantity was the same in quality ; in the case of the 

 social insects the food supplied, whether or not different in 



