72 A JAGUAR-HUNT ON THE TAQUARY 



species varies in extraordinary and inexplicable fashion 

 in different families of mammals. In the horse family, 

 for instance, the species are not fertile inter se ; whereas 

 among the oxen, species seemingly, at least, as widely 

 separated as the horse, ass, and zebra — species such as 

 the domestic ox, bison, yak, and gaur — breed freely 

 together, and their oiFspring are fertile ; the lion and 

 tiger also breed together, and produce offspring which 

 will breed with either parent stock ; and tame dogs in 

 different quarters of the world, although all of them 

 fertile inter se, are in many cases obviously blood-kin to 

 the neighbouring wild, wolf-like or jackal-like creatures 

 which are specifically, and possibly even generically, 

 distinct from one another. The big red wolf of the 

 South American plains is not closely related to the 

 northern wolves ; and it was to me unexpected to find 

 it interbreeding with ordinary domestic dogs. 



In the evenings after dinner we sat in the bare ranch 

 dining-room, or out under the trees in the hot darkness, 

 and talked of many things : natural history with the 

 naturalists, and all kinds of other subjects, both with 

 them and with our Brazilian friends. Colonel Rondon 

 is not simply " an officer and a gentleman " in the sense 

 that is honourably true of the best army officers in 

 every good military service. He is also a peculiarly 

 hardy and competent explorer, a good field naturalist 

 and scientific man, a student and a philosopher. With 

 him the conversation ranged from jaguar-hunting and 

 the perils of exploration in the " Matto Grosso," the 

 great wilderness, to Indian anthropology, to the dangers 

 of a purely materialistic industrial civilization, and to 

 Positivist morality. The Colonel's Positivism was, in 

 very fact to him, a religion of humanity, a creed which 

 bade him be just and kindly and useful to his fellow- 



