INTRODUCTION. xli 



cat, with her back in a blaze, in an instant made for the door (wliieh happened to be 

 0|(en) and sped np the street about one hundred yards, where she phmged into the vil- 

 la<Te watering trough, and extinguished the flame. The trough had eight or nine inches 

 of water in it and puss was in the habit of seeing the fire put out witli water 

 every night." 



The dog is/)ar excellence the friend of man, and without doubt liis mind has been 

 moulded as no other animal's, by that of his master. " The intelligence of the dog," 

 says Romanes, " is of special, and, indeed, of unique interest, from an evolutionary 

 point of view, in that from time out of record this animal has been domesticated 

 on account of the high level of its natural intelligence ; and by persistent contact with 

 man, coupled with training and breeding, its natural intelligence has been ' greatly 

 changed. In the result we see, not only a general modification in the way of depend- 

 ent companionship and docility, so unlike the fierce and self-reliant disposition of all 

 wild species of the genus ; but also a number of special modifications, i^eculiar to 

 certain breeds, which all have obvious reference to the requirements of man." Dogs 

 have long memories, and they are superior to all other animals in their highly devel- 

 oped emotions. They can communicate simple ideas to one another as well as to 

 their master, through the naedium of a canine sign-language. 



Reaching the highest order of mammals, the Primates, we are confronted Avith 

 what Romanes maj' be correct in supposing to be " a mental life of a distinctly differ- 

 ent type from any that we have hitherto considered, and that in their psychology, as 

 in their anatomy, these animals ajiproach most nearly to Homo sapiens." This, how- 

 ever, is an open question, and it is held by some that other animals, as the dog, exceed 

 the monkeys and apes in intelligence. We are not sure, however, but that the monkeys 

 and apes would, if bred in domestication for successive generations, prove that their 

 highly developed brains place them on a higher psychological level than the dog, cat, 

 elephant, hare, or pig. " The orang," says Romanes, " which Cuvier had, used to draw 

 a chair from one end to the other of a room, in order to stand upon it so as to reach a 

 latch wliicli it desired to open ; and in this we have a display of rationally adaptive action 

 which no dog has equalled, although ... it has been closely approached. Again, 

 Rengger describes a monkey employing a stick wherewith to pry up the lid of a chest, 

 which was too heavy for the animal to raise otherwise. This use of a lever as a mechan- 

 ical instrument is an action to which no animal other than a monkey has ever been known 

 to attain ; and, as we shall subsequently see, my own observation has fully corroborated 

 that of Rengger in this respect. More remarkable still, as we shall also subsequently see, 

 the monkey to which I allude as having myself observed, succeeded also by methodical 

 investigation, and without any assistance, in discovering for himself the mechanical 

 principle of the screw ; and that monkeys well understand how to use stones as 

 hammers is a matter of common observation since Dampier and Wafer first described 

 this action as practised by these animals in the breaking open of oyster-shells." 



As regards the brains of apes, Bastian remarks : " In the conformation of their 

 brain, the chimpanzee, the gorilla, and the orang approach, as we have seen, most 

 closely to that of man ; but it must never be forgotten that although in general shape, 

 in the disposition of its fissures, and in the arrangement of its convolutions, as far as 

 they go, there is this striking resemblance to the human brain, yet in actual size or 

 weiglit, the brain of the man-like apes is widely separated from that of man. The 

 heaviest brain belonging to one of these creatures, as yet examined, has been barely 

 one half of the weight of the smallest normal human brains, although the weight of 



