062 APPENDIX B. 



inheritance. Thus self-feeding may readily have ceased among 

 these soldier-ants before the caste-organization arose among them. 

 With this interpretation compare the interpretation of Pro- 

 fessor Weismann. I have before protested against arguing in 

 abstracts without descending to concretes. Here let us ask what 

 are the particular changes which the alleged explanation by sur- 

 vival of the fittest involves. Suppose we make the very liberal 

 supposition that an ant's central ganglion bears to its body the 

 same ratio as the human brain bears to the human body say, 

 one-fortieth of its weight. Assuming this, what shall we assume 

 to be the weight of those ganglion-cells and fibres in which are 

 localized the perceptions of food and the suggestion to take it ? 

 Shall we say that these amount to one-tenth of the central 

 ganglion ? This is a high estimate considering all the impres- 

 sions which this ganglion has to receive, and all the operations 

 which it has to direct. Still we will say one-tenth. Then it 

 follows that this portion of nervous substance is one-400th of the 

 weight of its body. By what series of variations shall we say 

 that it is reduced from full power to entire incapacity ? Shall 

 we say five ? This is a small number to assume. Nevertheless 

 we will assume it. What results ? That the economy of nerve- 

 substance achieved by each of these five variations will amount to 

 one-2000th of the entire mass. Making these highly favourable 

 assumptions, what follows : The queen-ant lays eggs that give 

 origin to individuals in each of which there is achieved an 

 economy in nerve-substance of one-2000th of its weight ; and 

 the implication of the hypothesis is that such an economy will so 

 advantage this ant-community that in the competition with other 

 ant-communities it will conquer. For here let me recall the 

 truth before insisted upon, that natural selection can operate only 

 on those variations which appreciably benefit the stirp. Bearing 

 in mind this requirement, is any one now prepared to say that 

 survival of the fittest can cause this decline of the self-feeding 

 faculty ? * 



Not limiting himself to the Darwinian interpretation, however, 

 Professor Weismann says that this degradation may be accounted 

 for by " panmixia alone." Here I will not discuss the adequacy 



* Perhaps it will be alleged that nerve-matter is costly, and that this 

 minute economy might be of importance. Anyone who thinks this will no 

 longer think it after contemplating a litter of half-a-dozen young rabbits (in 

 the wild rabbit the number varies from four to eight) ; and on remembering 

 that the nerve-matter contained in their brains and spinal cords, as well as 

 the materials for building up the bones, muscles, and viscera of their bodies, 

 has been supplied by the doe in the space of a month; at the same 

 time that she has sustained herself and carried on her activities: all this 

 being done on relatively poor food. Nerve-matter cannot be so very costly 

 then. 



