26o THE HISTORY OF CREATION. 



no wild oxen and horses, as in the neighbouring parts of 

 South America, both north and south of Paraguay. This 

 surprising circumstance is explained simply by the fact that 

 in that country a kind of small fly is very frequent, and is 

 in the habit of laying its eggs in the navel of newly-born 

 calves and foals. The newly-born animals die in conse- 

 quence of this attack, and the small deadly fly is therefore 

 the cause of oxen and horses never becoming wild in that 

 district. Supposing that this fly were destroyed by some 

 insect-eating bird, then these large mammals would grow 

 wild in Paraguay, as well as in the neighbouring parts of 

 South America ; and as they would eat a quantity of certain 

 species of plants, the whole flora, and, consequently again, 

 the whole fauna of the country would become changed. It 

 is hardly necessary to state, that at the same time the whole 

 economy, and consequently the character, of the human 

 population would alter. 



Thus the prosperity, nay, even the existence of whole 

 populations can be indirectly determined by a single small 

 animal or vegetable form in itself extremely insigniflcant. 

 There are small coral islands whose human inhabitants live 

 almost entirely upon the fruit of a species of palm. The 

 fructiflcation of this palm is principally efiected by insects, 

 which carry the pollen from the male to the female palm 

 trees. The existence of these useful insects is endangered 

 by insect-eating birds, which in their turn are pursued by 

 birds of prey. The birds of prey, however, often succumb 

 to the attack of a small parasitical mite, which develops itself 

 in millions in their feathers. This small, dangerous parasite, 

 again, may be killed by parasitical moulds. Moulds, birds 

 of prey, and insects would in this case favour the prosperity 



