I, AKIMALCULA OF INFUSIONS. 211 



iy the inverfe of thofe you propofe on the. 

 eggs of infefts- The life of the embryo in 

 •he egg evidently differs much from that of the 

 animal developed. Therefore it is a law of the 

 animal economy, that the germ of the embryo 

 can fupport fituations or accidents deftruftive of 

 the animal evolved. Were we able to compare 

 thefe two lives exactly, much light would be 

 thrown on the experiments which we fhould make 

 of this nature, and the eifeds that would enfue. 



But how far is our phyfiological knowledge 

 from extending to that ! We know the gei-m or 

 embryo only by fome of the moil prominent, 

 I (hould fay the groifeft features ; and we are 

 ignorant of its principal connexion with thf 

 various parts furrounding it in the egg. The 

 little of the whole that we know only relpe^ls 

 -the chicken. How can we hope that tlie light 

 of obfervation will one day penetrate the feoret 

 organization of an infecl's egg infinitely minute 

 when compared with that of a hen ? Wliat a 

 profound abyfs to us is the egg of an infe^ ; but 

 what fubjeft in natural hiftory, pliiiofophy, or 

 metaphyfics, does not prefent iimilar abylfesi" 

 The fage will Med: the leaft profound, and 

 €onfider them with modeit and relpe^tful re- 

 ferve. 



I have juft re-perufed the eighth and ninth 



chapters of your firft DilTertation on Animalcula, 



O 2 which 



