330 THE POPULAR SCIENCE MONTHLY. 



arc concerned, than many other vertebrates. In fact, in Romanes's work 

 on " Animal Intelligence," the highest powers of intellect are ascribed 

 to the carnivora, which as a general rule are solitary animals. And 

 this is a natural result of the fact that they are obliged to depend 

 ni^on their own powers in all the exigencies of life, and can not trust 

 to others to relieve them from some of the duties of existence. 



Much has been said about the highly remarkable powers of the 

 minute mass of nerve-substance in an ant's head. Yet the brain of 

 every animal has undoubtedly a double duty to perform. It is partly 

 devoted to the control of the muscular organization, partly to psychical 

 activity. And to this we must ascribe the increase in size of brain that 

 generally attends increase in size of body among animals. Though 

 the brain of a large animal may be much larger than that of a small 

 one, this may be mainly due to the increase of its motor duties, and 

 there may be no increase in its psychical portion. In fact, in certain 

 large extinct animals, with greatly developed posterior structure, a 

 sort of second brain seems to have existed at the rear extremity of the 

 spinal column, as if the motor portion of the brain had moved back- 

 ward to the region where it was most needed. Yet it is very probable 

 that in any of the higher vertebrates the portion of the brain devoted 

 to psychical functions is considerably greater in volume than the whole 

 brain of the ant. And, if the degree of intelligence be in any sense 

 proportional to the size of its organ, these higher vertebrates should 

 be superior in intellect to the ant. 



Such is actually the case. The excursions of the ant-raind bej^ond 

 the limit of its instincts seem to be exceedingly slight. Those of the 

 mammalian mind are sometimes extensive. If we compare the instances 

 of individual intellect displayed by a cat and an ant, for instance, we 

 can not avoid the conclusion that the cat is very greatly superior in 

 powers of reasoning. Yet no cat tribes keep cows, marshal armies, 

 store provisions, enslave captives, or perform any of the wonderful 

 series of intellectual acts which are common in ant communities, and 

 ■which form part of the powers of every ant-brain. How shall we ac- 

 count for this difference in results ? It seems evident that it is in some 

 way due to difference in modes of association. The powers of the ant 

 are instinctive — that is, they have been passed down by hereditary 

 transmission through numerous generations. They are the outcome of 

 not one brain, but of innumerable brains. Though the brain of one 

 ant be minute, yet the brains of a million ants would form a consider- 

 able mass, and every act of ant intellect is probably the product of 

 several millions of ant-brains, each of which may have added some mi- 

 nute increment to the final result. 



There are, in fact, two distinct methods by which the intellectual 

 powers of ancestors may be transmitted to descendants. One of these 

 is the hereditary, the other the experimental. Among solitary animals 

 the special intellectual achievements of each animal are in great meas- 



