40 STUDIES ON FERMENTAIIOX. 



abundance. The reason is obvious ; rain falls on a meadow 

 and forms little pools of water about the roots of the herbs that 

 grow there ; this water remains for some time, and very soon 

 swarms with a multitude of infusoria, especially colpoda. Dry- 

 ness follows ; the colpoda becomes encysted, and forms a dust 

 that is wafted by the winds on to the blades of grass, so that 

 the mower will carry away not only his hay, but also myriads 

 of colpoda, as well as spores of mucedines and other organisms,* 

 The maceration of pepper will give us some infusoria hardly 

 ever found in other infusions, the reason of this being that such 

 infusoria exist where the pepper grows — in other words, their 

 germs are exotic. That the infusion of a special plant should 

 give us special infusoria, is scarcely more surprising than the 

 discovery of a particular parasite or insect existing on a 

 particular plant, and not on others of a different species that 

 grow near it. Thus it happens that the ferment-germs of must 

 exist on the surface of grapes, whether detached or in clusters. 

 It is only natural that we should find the organ or the plant 

 that is destined later on to become the food of a parasite serving 

 as a habitation for the germs of that parasite. 



^ II. — Experiments on Blood and XJkine taken in their 

 Normal State, and Exposed to Contact with Air 



THAT HAS BEEN DEPRIVED OF THE PaRTICLES OF DuST 



"WHICH IT Generally holds in Suspension. 



Recourse to the application of heat, in the first place, is an 

 excellent means, as we have just seen, of procuring organic 

 liquids free from all disturbing germs ; but there is a still more 

 remarkable and instructive, wc may even say more unlocked 

 for, method of securing this result, which may be described as 

 in some measure borrowed from the nature of things. It consists 

 in seeking purity in the natural liquids of animals and plants. 

 It is difficult to understand how the liquids circidating in the 

 organs of animal bodies, such as blood, urine, milk, amniotic 



• On this subject see the observations of M. Coste {Compte-rendus de 

 ' Academie, t. lix. pp. 149 and 308, 18G4). 



