OF NATURAL HISTORY. 251 



order to explain the manner in which female plants, when fituated 

 at a diftance from males, are impregnated. Some of them, as Kalra, 

 and others, are perfedly fatisfied with this fiippofed aerial commerce 

 of vegetables, even when the males are ten, fifteen, or twenty miles 

 diftant from the females ! Here, it may be remarked, that the mul- 

 tiplication of fpecies is one of the moft important laws of Nature. 

 AH the laws of Nature are fixed, fteady, and uniform, in their ope- 

 ration : None of their effeds are abandoned to thofe uncertainties 

 which necefTarily refult from chance, or from any fortuitous train of 

 circumftances. But, is there any thing, in northern climates at leaft, 

 more defultory and capricious than the direction and motion of the 

 winds ? Can we form a conception of any thing more cafual and 

 uncertain than the wayward paths of infeds ? The very fuppofition, 

 therefore, that Nature has expofed the fertility of a tenth part of 

 the whole vegetable kingdom, and many of them, too, plants of the 

 utmoft importance to man, and other animals, to fuch accidental 

 caufes, is repugnant to every idea of found philofophy. Befides, 

 the reverfe has been proved by Dr Alfton, Camerarius, and Tour- 

 nefort. Thefe gentlemen reared female plants of the fpinage and 

 hemp in fuch fituations, and with fuch fcrupulous precautions, to 

 prevent any fuppofed impregnation by means of the wind, or of in- 

 fers, that it is difficult to conceive the poffibility of any communi- 

 cation between the males and females. Thefe females, however, 

 produced fertile feeds in the greateft abundance. 



Since thefe experiments were made, it has been difcovered, that 

 male flowers are fometimes found lurking on the female plants of 

 the fpinage and hemp : And this difcovery the fexuallfts think fuffi- 

 cient to account for the fuccefs of Dr Alfton's experiments. But, 

 inftead of folving the difficulty, this circumftance feems to involve 

 it in ftill deeper obfcurky : For, that the pollen iffiiing from the an- 

 therae of a male flower or two fhould rife, fall, and turn round in 



I i 2 every 



