by Infusoria capable of existing without free Oxygen. 315 



the ferment has been added, I have failed to prevent the contact 

 of the air with the solution experimented upon. But I will now 

 demonstrate that the very strict precautions I have taken to obviate 

 the contact of oxygen or of air are really uncalled for. The 

 following observations will also afford a reply to the question why 

 the germs of Infusoria which not only live without air, but are 

 actually destroyed by it (as happens also with the butyric Infu- 

 soria), may spontaneously originate in liquids which under the 

 circumstances of ordinary fermentation are exposed to the atmo- 

 sphere. 



• " Resuming the phial filled with water, and containing the 

 tartrate of Hme and the phosphates, and having the bent tube 

 luted in its neck also filled with water (which I will suppose to 

 be ordinary distilled water undeprived of its air by boiling), and 

 with its free extremity plunged under mercury, it will be found 

 by experiment that, without adding any ferment, fermentation 

 of the tartrate of lime takes place at the end of a few days, and 

 that a multitude of animalcules are found living in the phial, 

 though deprived of oxygen. 



" How this happens it is easy to conceive ; for in all such 

 cases the smallest Infusoria, such as Monas, Bacterium termo, 

 &c., develope themselves in the aerated distilled water, which 

 contains in solution traces of ammonia, of phosphate and 

 carbonate of lime, together with oxygen gas ; this last they 

 appropriate to themselves with incredible rapidity, until it is 

 ultimately used up, replacing it by carbonic acid in somewhat 

 larger volume. This result is accomplished in from twenty-four 

 to thirty-sLX hours at most, at a temperature of 25° to 30° Cent. ; 

 and it is not till then that the Infusoria of fermentation make 

 their appearance, which have no need of oxygen for their exist- 

 ence. The question, therefore, why animalcules which do not 

 require oxj'gen to carry on life, and to which air is destructive, 

 should arise under the conditions assumed, is thus at once and 

 naturally answered. They originate in sequence to a former 

 generation of organisms which quickly abstract the relatively 

 considerable quantity of oxygen in the fluid, and leave it com- 

 pletely destitute of that element. 



" I shall shortly revert to this very general fact of the succes- 

 sion of organisms which consume oxygen, and of such as do not, 

 at least in a free state. 



" In the instance under consideration, it is easy to comprehend 

 the facility with which spontaneous fermentation of tartrate of 

 lime may be set up, whenever special precautions are not taken 

 to prevent the access of the germs disseminated through the air, 

 or those in the dust deposited from the air on all objects. It is 

 equally easy to \mderstand the fermentation of tartrate of lime 



21* 



