FERMENTS, FERMENTATIONS, AND LIFE. 549 



to the germs suspended in the air, or deposited on the surface of the 

 grapes and stems. M. Pasteur draws blood from an animal's reins by 

 a similar process, and introduces it into a glass vessel in contact with 

 pure air. The blood continues fresh for years. M. Pasteur asserts 

 and proves by experiment that grape-juice, milk, blood, and all liquids 

 that most readily undergo change in ordinary conditions, are incapa- 

 ble of fermentation in air which is pure, that is to say, deprived of the 

 corpuscles it contained. 



M. Pasteur has made still another set of experiments. He has ob- 

 tained development of fermentation in liquids freed from albuminoid 

 substances. It was supposed, before his researches, that the cells re- 

 marked in the fermentation of grape-juice proceed from the conversion 

 of the albuminoid substances which this fluid contains in its natural 

 state. M. Pasteur prepares a solution of sugar, tartrate of ammonia, 

 and some other salts, and sprinkles a few yeast-globules in it. They 

 swell, develop, and propagate in this artificial medium quite as well 

 as in the grape-juice. So it was supposed that in the acid fei-menta- 

 tion of milk the ferment is a product of the conversion of casein. M. 

 Pasteur proves that supposition to be unfounded, by artificially pro- 

 ducing the lactic ferment in a compounded liquid containing not a 

 trace of casein. These very delicate experiments have not only in- 

 creased the vogue of the panspermic theory, but they have been of 

 great value also to vegetable physiology. 



Many objections have been raised to these theories on the origin 

 of ferments, to which M. Pasteur has almost always replied by unques- 

 tionable facts and solid reasonings, though he has sometimes done 

 himself the injustice to be rough and contemptuous in discussion tow- 

 ard his opponents. Truth is strong enough to indulge charity for 

 error. The gravest of these objections, it must be said, have applied 

 to problems which do not concern the very foundation of the dispute 

 between the panspermist system and its opposite. For instance, M. 

 Trecul, the skillful and noted micrographer, M. Bechamp, and others, 

 have proved that M. Pasteur mistakes with regard to the evolutions 

 and transformations imdergone by microscopic beings in fermenting 

 media. M. Pasteur has certainly made more than one mistake on this 

 subject, and there probably does exist between certain ferment-corpus- 

 cles a closer relationship than is supposed at the laboratory of the 

 Normal School ; but that does not in the least alter the fundamental 

 character of the theory. Attention is also called to the fact that cor- 

 puscles with a determinate structure can be produced complete, with- 

 out germs, in some liquids. No doubt this is true, but only on condi- 

 tion that the liquids are living ones. Ko doubt the cambium of vege- 

 tables, the blastema of animals, and generally all protoplasmic fluids, 

 are fertile hatching-fields for the spontaneous development of the cells 

 and fibres of living tissues. It is thus that the first elements of the 

 embryo show themselves in the animal ovule. And in this respect the 



