280 MENTAL FACULTIES SEC. 



would disturb the egg, and accordingly the wasp paralyses 

 grubs and packs them like sacks of meal one after another in 

 the cell. How did she arrive at this habit ? At the begin- 

 ning she probably killed larvae by stinging them anywhere, 

 and then placed them in the cell. The bad results of this 

 showed themselves ; the larvse putrefied before they could 

 serve as food for the larval wasps. In the meantime the 

 mother-wasp discovered that those larvae which she had stung 

 in particular parts of the body were motionless but still alive, 

 and then she concluded that larvse stung in this particular 

 way could be kept for a longer time unchanged as living 

 motionless food. It may be suggested that the wasp only 

 paralysed the larvae in order to carry them more easily ; but 

 even if this were the case, she must, since she now invariably acts 

 in this way, have drawn a conclusion by deductive reasoning. 



In this case it is absolutely impossible that the animal 

 has arrived at its habit otherwise than by reflection upon the 

 facts of experience. 



An accurate observer, Lichtenstein, states, with regard to 

 the laying and incubation of the ostrich, that during the 

 breeding- time one cock and three or four hens live together, 

 and he continues : " All the hens lay their eggs in the same 

 nest, which consists of nothing more than a round depression 

 in the somewhat loose clayey soil, of such a size that one hen 

 can cover it. Round the hole the birds scratch up the soil, 

 so as to make a kind of wall, against which the outermost 

 eggs are supported. Each egg in the nest stands on end, so 

 that the largest number possible can be packed in it. As 

 soon as there are ten to twelve eggs in the nest the birds 

 begin to incubate, and this they do in turns, the hens reliev- 

 ing one another by day, the cock alone sitting at night, in 

 order that he may repel the attacks of the jackal and the wild 

 cat, who greedily watch for an opportunity to steal the eggs. 

 In the meantime the hens still continue to lay eggs, not only 



