I. ANIMALCULA OF INFUSIONS. II5 



equilibno is mod advantageous for them to origi- 

 nate. 



Similar phenomena have occurred with the 

 eggs of animals^ I have repeatedly put thofe of 

 terreftrial and aquatic infefts in the receiver of 

 an air-pump, but none were ever hatched, though 

 they had all the requifites neceffary except air. 



From thefe and other analogous fads is de- 

 duced the neceffity of air for the developement of 

 every animated being. While the animal is con- 

 centrated in the egg, it enjoys the beneficial in- 

 fluence of air by an infinity of minute pores 

 throughout the egg^ which have not efcaped the 

 notice of naturahfls : when liberated from it, or 

 the involucrum by which it was concealed in the 

 womb of the mother, it receives the benefit of 

 the air by other more evident ways. An im- 

 menfe number of animals refpire by the mo^ithj 

 and many by apertures in the fides of the body^ 

 by the extremity of the abdomen, or by other 

 parts. The breath enters the mouth of nume- 

 rous channels at the furface, which condud the 

 air by ramifications into the interior of the body„ 

 The animalcula of infufions, no twit h (landing 

 their apparent fimplicity of ftrudture, exhibit an 

 organ which we are ftrongly induced to conceive 

 Is intended for refpiration. And in tliis cafe, they 

 more than ever (land in need of the aerial fluid, 

 i^teh is evident by depriving them of it. There 

 H 2 are 



