90 OF INTELLIGENCE AND INSTINCT. 



stinct. Some of them collect only honey and wax, others 

 are charged with the care and education of the young, whilst 

 others are the natural chiefs of the colony. 



201. Finally, there are certain animals so guided by their 

 instinct as to live like pirates, on the fruits of others' labour. 

 The lestris or jager will not take the trouble to catch fish for 

 itself, but pursues the gulls, until, worn out by the pursuit, 

 they eject their prey from then* crop. Some ants make war 

 upon others less powerful, take their young away to their 

 nests, and oblige them to labour in slavery. 



202. There is a striking relation between the volume of 

 the brain, compared with the size of the body, and the degree 

 of intelligence which an animal may attain. The brain of 

 man is the most voluminous of all, and among other animals 

 there is every gradation in this respect. In general, an animal 

 is the more intelligent, in proportion as its brain bears a greater 

 resemblance to that of man. 



203. The relation between instinct and the nervous sys- 

 tem does not present so intimate a correspondence as exists 

 between the intellect and the brain. Animals which have a 

 most striking development of instinct, as the ants and bees, 

 belong to a division of the animal kingdom where the nervous 

 system is much less developed than that of the vertebrata, 

 since they have only ganglia, without a proper brain. 

 There is even a certain antagonism between instinct and in- 

 telligence, so that instinct loses its force and peculiar character 

 whenever intelligence becomes developed. 



204. Instinct plays but a secondary part in man; he is 

 not, however, entirely devoid of it. Some of his actions are 

 prompted by instinct, as, for instance, the attempts of the in- 

 fant to nurse. The fact again, that these instinctive actions 

 mostly belong to infancy, when intelligence is but slightly 

 developed, goes to confirm the two last propositions. 



