[ 34^ ] 



XXX. ILxperiments and Ohfcrv^atlons on the Utality and JJfe 

 of Germs. By Victor Mic.-ielotti^ M.D. oflurin^. 



A. 



5 I propofe to examine in this memoir the vital power, 

 I have thought proper, in order that the fubje6l may be ren- 

 dered eafier, to take vitahty at that period of life when the 

 iiun)ber and complications of its funftions are the lead; 

 ihat is to fay, in the embryo :— it is then reduced to fimple 

 nutrition and a fpeedier increafe. 



We are as yet little acqiraintcd with the powers by which 

 the embryo is animated and expanded ; the only obje6t of 

 the obfervations hitherto made on different kinds of eggs 

 and feeds, was to prove or refute the fvftem of the pre-exift- 

 ence of germs or at n^^^ to throw light on the formation 

 and expanfion of fome of their parts. It is on this power, 

 however, with which living bodies are endowed, and the 

 a6lion of b^ies which have fome iniiuence on it, that the 

 phasnomena of life depend. 



But how comes it that certain agents which >a6t with fo 

 much energy on adults fcem to have no a6lion on the foetus, 

 iincethe vital power and the //iw?^/^^ employed are the fame? 

 Is there then at certain peridds of life, a particular llimulus, 

 deftined to aft on particular organs ? or does fenfibility vary 

 in the different periods of life ? 



In fupport of the firft hypothef.s we might take light, 

 for example, which appearing to be one of the vivifying 

 principles of animals and vegetable?, feems, hov.ever, to have 

 no influence on the expanfion of germs, fince the greater 

 part of them pafs the firfi: period of life in obfcuritv. 



But if we fuppofc a different fenfibility in the various fiates 



sof life, we fliall obferve that the vivifying principle of the 



animal ought to be more energetic in proportion as it is 



nearer its fource, fince the whole fpace paffed over ought to 



be at the expenfe of the force employed to make it pafs. 



One of the firfi: modifications under which the vital power 

 prefents itfelf is that of irritaliUty; and it is exaftly during 

 the firft: expanfion of the foetus that the greatell, and as we 

 ■'■ From Journal i^e PbyJ:quc'f\ tnloiKy an. 9. 



6 may 



