OF NATURAL HISTORY. 49 



latlng fyftem, are converted into blood, and afford that conflant 

 fupply of nourifhment which the perpetual wafte of our bodies de- 

 mands. 



We fhall next give a fketch of thofe important organs by which 

 we are enabled to multiply and continue the fpecies. The circula- 

 tion of the blood, and the mode by which the quantity of it is cori- 

 tinually kept up by frefh fupplies of chyle, are effedts which, in 

 fome meafure, correfpond with our ideas of the machinery employ- 

 ed. The organs of generation exhibit a ftill more complex fpeci- 

 men of exquifite mechanifm. But the machinery employed, with- 

 out the aid of experience, could never fugg^ft the moft diftant idea 

 of the effe£t to be produced. 



In the male, the organs of generation confifl: of the tefles, the fe- 

 minal veflels, and the penis. The teftes are two glandular bodies 

 which poflefs the power of converting the blood into femen. They 

 are originally formed and lodged in the abdomen ; and it is not till 

 after birth that they commonly pafs into the groin, and from thence 

 fall into the fcrotum, which is a mufcular bag prepared for their re- 

 ception and defence. The tefles of the hedgehog and of fome other 

 quadrupeds remain in the abdomen during life. Inflances of the 

 fame kind fometimes happen in the human fpecies. Each tefticle is 

 compofed of the fpermatic artery and vein. The blood paffes very 

 flowly through the fpermatic artery, and produces an infinite num- 

 ber of convolutions in the fubftance of the tefticle, where it depofits 

 the femen, which is taken up by the femeniferous tubes. Thefe 

 tubes at length unite, and, by an immenfe number of circumvolu- 

 tions, form a kind of appendix to the tefticle, commonly known by 

 the term epidydymis. The tubes of the epidydymis, after termina- 

 ting in an excretory dudt called 'vas deferens, afcend toward the ab- 

 dominal rings, and depofit the femen in the feminal veficles, which 

 J ! G are 



