542 VRA OMENTS OF 8CIKNCK. 



the others. The difference was extraordinary. The un- 

 covered fruits had become soft, watery, and very sweet; 

 the others were firm and hard, their fleshy portions being 

 not at all watery. They had, moreover, lost a considerable 

 quantity of their sugar. They were afterward bruised, 

 and the juice was distilled. It yielded six and a half 

 grammes of alcohol, or one per cent, of the total weight 

 of the plums. Neither in these plums, nor in the grape 

 first experimented on by Pasteur, could any trace of the 

 ordinary alcoholic leaven be found. As previously proved 

 by Lechartier and Bellamy, the fermentation was the work 

 ol the living cells of the fruit itself, after air had been 

 denied to them. When, moreover, the cells were destroyed 

 by bruising, no fermentation ensued. The fermentation 

 was the correlative of a vital act, and it ceased when life 

 was extinguished. 



Liidersdorf was the first to show by this method that 

 yeast acted, not, as Liebig had assumed, in virtue of its 

 organic, but in virtue of its organized character. He 

 destroyed the cells of yeast by rubbing them on a ground 

 glass plate, and found that with the destruction of the 

 organism, though its chemical constituents remained, the 

 power to act as a ferment totally disappeared. 



One word more in reference to Liebig may find a place 

 here. To the philosophic chemist thoughtfully pondering 

 these phenomena, familiar with the conception of molecular 

 motion, and the changes produced by the interactions of 

 purely chemical forces, nothing could be more natural 

 than to see in the process of fermentation a simple illus- 

 tration of molecular instability, the ferment propagating 

 to surrounding molecular groups the overthrow of its own 

 tottering combinations. Broadly considered, indeed, there 

 is a certain amount of truth in this theory; but Liebig, 

 who propounded it, missed the very kernel of the phe- 

 omena when he overlooked or contemned the part played 

 in fermentation by microscopic life. He looked at the 

 matter too little with the eye of the body, and too much 

 with the spiritual eye. He practically neglected the 

 microscope, and was unmoved by the knowledge which its 

 revelations would have poured in upon his mind. His 

 hypothesis, as I have said, was natural nay it was a strik- 

 ing illustration of Liebig's power to penetrate and unveil 

 molecular actions; but it was an error, and as such has 



