ORIGIN OF THE YEASTS OF WINE 221 



took the precaution, while leaving some of the clusters 

 free, to cover a certain number on each vine with cot- 

 ton which had been brought to a temperature of about 

 150C." 



'*. . . Toward the tenth of October, the grapes in the 

 hothouses were ripe; through the skin of the berry, one 

 could clearly distinguish the seeds, and in taste they were 

 as sweet as the majority of the grapes grown outside; 

 only, under the cotton, the grapes, naturally black, were 

 scarcely colored, rather violaceous than black, and the 

 white grapes had not the golden yellow tint of white 

 grapes exposed to the sun. Nevertheless, I repeat, the 

 maturity of both left nothing to be desired. 



"On the tenth of October, I made my first experiment 

 on the grapes of the uncovered clusters and on those 

 covered with the cotton, comparing them with some which 

 had grown outside. The result I may say surpassed 

 my expectation. . . . To-day, after a multitude of trials, 

 I am just where I started, that is to say, it has been 

 impossible for me to obtain a single time the alcoholic 

 yeast fermentation from clusters covered with cotton, 

 and as for the uncovered clusters of the same vines I 

 have had only a single case of fermentation, by a yeast 

 which I described a long time ago in the Bulletin de la 

 Societe chimique, and which has since received from Dr. 

 Reess the name of Levure apiculee. 



"A comparative experiment naturally suggested it- 

 self. When the hothouses were set up we were in the first 

 period, that in which the germs are absent from the 

 stem and the clusters. At the time when the experiments 

 which I have just described took place, from the 10th to 

 the 31st of October, we were, on the contrary, in the 

 period when the germs were present. It was then pre- 

 sumable that if I detached hothouse clusters covered 



with cotton and exposed them, after removing the cot- 

 17 



