GROWTH AND FOOD OF ANIMALS. 147 



Siberia, Kamtschatka, and the polar regions, are supposed 

 to be the abodes of misery and desolation. They are, it must 

 be allowed, infested with numerous tribes of bears, foxes, 

 gluttons, and other rapacious animals. But it should be con- 

 sidered, that these voracious animals supply the natives with 

 food and clothing. To elude the attacks of ferocity, and to 

 acquire possession of the skins and carcasses of such crea- 

 tures, the industry and dexterity of savage nations are excited. 

 The furs are demanded by foreigners. The inhabitants by 

 this means learn commerce and the arts of life; and in the 

 progress of time, bears and wild beasts become the instru- 

 ments of polishing a barbarous people. Thus the most sub- 

 stantial good often proceeds from apparent misfortune. 



There is hardly a plant that is not rejected as food by some 

 animals, and ardently desired by others. The horse yields 

 the common water-hemlock to the goat, and the cow the long- 

 leafed water-hemlock to the sheep. The goat, again, leaves 

 the aconite, or bane-berries, to the horse, &>c. Plants which 

 afford proper nourishment to some animals, are by others 

 avoided, because they would not only be hurtful, but even 

 poisonous. Hence no plant is absolutely deleterious to ani- 

 mal life. Poison is only a relative term. * The euphobia, or 

 spurge, so noxious to man, is greedily devoured by some of 

 the insect tribes. 



It is a remark of the ingenious Reaumur, that such insects 

 as feed upon dead carcasses, and whose fecundity is great, 

 never attack live animals. The flesh-fly deposits her eggs in 

 the bodies of dead animals, where her progeny receive that 

 nourishment which is best suited to their constitution. But 

 this fly never attempts to lay her eggs in the flesh of sound 

 and living animals. If Nature had determined her to observe 

 the opposite conduct, men, quadrupeds, and birds would have 

 been dreadfully afflicted by the ravages of this single insect. 

 Lest it might be imagined that the flesh-fly selected dead, 

 instead of live animals, because, in depositing her eggs, she 

 was unable to pierce the skin of the latter, M. deT&eaumur 

 made the following experiment, which removed every doubt, 

 that might arise on the subject. He carefully pulled off all 

 the feathers from the thigh of a young pigeon, and applied to 

 it a thin slice of beef, in which there were hundreds of mag- 

 gots. The portion of beef was not sufficient to maintain them 

 above a few hours. He fixed it to the thigh by a bit of gauze ; 

 and he prevented the pigeon from moving, by tying its wings 

 and legs. The maggots soon showed that their present situ- 



