JNTRODUCTORY OBSERVATIONS. XXV 



primordium may conftitute a part of the animal it- 

 felf : it may remain entire, though incapable of ex- 

 panfion, and not be liable to decay for a feries of 

 years ; then, when the flmd which it (hould 

 naturally inhabit is fecreted, fome of the nu- 

 merous germs, which we may well fuppofe difTe- 

 minated throughout the body, will be unfold- 

 ed there, though the circumflances necefTary for 

 their developcment are feldom or never found elfe- 

 where. In the fame manner, it is not impro- 

 bable, arc the numerous worms inhabiting the 

 human body produced. The egg is conveyed 

 into the body, or tranfmitted by the parent; 

 and, when in a fuitable fituation, it expands. 

 Yet this reproduftion is myfterioua, when com- 

 pared with that of other animals. 



The fame rules, with little variation, regulate 

 the propagation of mankind, quadrupeds, and 

 birds. Fifhes and amphibia in general generate 

 in a mode peculiar to themfelves. Infe<9;s ap- 

 proach in fome refpeO:s to the higher orders of 

 animals ; but defcending to the innumerable and 

 various claiTes of worms in all the branches, no- 

 thing can be more diverfified. Some divide into 

 pieces, and each becomes a new animal ; others 

 fend forth buds, which grow complete like the 

 parent, and thus perpetuate the fpecies ; fome pro- 

 duce living young j fome eggs j and a few, both 

 eggs and young. 



The 



