INTRODUCTORY OBSERVATIONS. Ixk 



will live and produce a new worm. Some fmgula- 

 rities arife from thefe mutilations. If the two ends 

 are cut off a worm, the middle piece will become 

 a perfefl: animal; but the head will not germinate 

 from what we Ihould fuppofe the natural place, 

 that is, the anterior part ; on the contrary, it 

 proceeds from the portion that was next the 

 original tail j and the new tail will grow from 

 the anterior part of the trunk. It has been fup- 

 pofed, that the difficulty of eradicating that ter- 

 rible fcourge of mankind, the tenia, is owing to 

 the prompt and fudden reproduction of mutilated 

 parts. Numbers of marine animals, fuch as af- 

 terise, medufas, even fifhes, enjoy this property ; 

 and it is thought that it defcends to the animalcula 

 of infufions. In fhort, there is every reafon to 

 believe that it is widely difFufed through the ani- 

 mal fcale ; and, if experiments could be made 

 without endangering life, or inducing difeafe, 

 that its empire would be found far more extenfive 

 than poffibly can be conceived. 



The firft obfervations on animal reprodudion 

 were readily credited, becaufe they related to 

 parts without which it was known an animal 

 might exifh ; but when fuch obfervations were 

 extended to the organs moil: material and impor- 

 tant to life, and when the lofs of thefe daily tef- 

 tified that the animal inevitably periflied, an unu- 



fua! 



