40© GENERATION. Sect. XXXIX. 4. g. 



plants of this country, nor accurately correfpond with thcfe of 

 other climates, which is an argument countenancing the chang- 

 es in the forms, botli of animals and vegetables, during the pro- 

 greiTive lhufture of the globe, which we inhabit. See Town- 

 fon's Philof. of Mineralogy, p. 1 10. 



This idea of the gradual formation and improvement of the 

 animal world accords with the obfervations of lome modern phi- 

 loibphers, who have fuppofed that the continent of America has 

 been raifed out of the ocean at a later period of time than the 

 other three quarters of the globe, which they deduce from the 

 greater comparative heights of its mountains, and the confe- 

 rment greater coldnefs of its refpeclive climates, and from the 

 lefs fize and ilrength of its animals, as the tygers and allegators 

 compared with thofe of Afia or Africa. And laftly, from the 

 lefs progrefs in the improvements of the mind of its inhabitants 

 in refpeCt. to voluntary exertions. 



This idea of the gradual formation and improvement of the 

 animal world feems not to have been unknown to the ancient 

 philofophers. Plato having probably obferved the reciprocal 

 generation of inferior animals, as fnails and worms, was of opin- 

 ion, that mankind with all other animals were originally herma-< 

 phrodites during the infancy of the world, and were in procefs 

 of time feparated into male and female. The breads and 

 teats of all male quadrupeds, to which no ufe can be now af- 

 figned, adds perhaps fome fhadow of probability to this opinion. 

 Linnseus excepts the horfe from the male quadrupeds, who have 

 teats -, which might have fhewn the earlier origin of his exig- 

 ence ; but Mr. J. Hunter afferts, that he has difcovered the vef- 

 tiges of them on his iheath, and has at the fame time enriched 

 natural hiftory with a very curious fa£t concerning the mile 

 pigeon ; at the time of hatching the eggs both the male and fe~ 

 male pigeon undergo a great change in their crops -, which thick- 

 en and become, corrugated, and fecrete a kind of milky fluid, 

 which coagulates, and with which alone they for a few days 

 feed their young, and afterwards feed them with this coagulated 

 fluid mixed with other food. How this refembles the breafts 

 of female quadrupeds after the production of their young ! and 

 how extraordinary, that the male mould at this time give milk 

 as well as the female ! See Botanic Garden, Part II. Note on 

 Curcuma. 



The late Mr. David Hume, in his pofthumous works, places 

 the powers of generation much above thofe of our boafled rea- 

 fon ; and adds, that reafon can only make a machine, as a clock 

 or a ihip, but the power of generation makes the maker of the 

 machine j and probably from having obferved, that the greateft 



. . part 



