792 Transactions of tee American Institute. 



Dr. J. W. Richards — There is another new remedy to which I 

 will call attention — skim-milk, which contains a considerable amount 

 of caseine, used as an exclusive diet. 



The President — Of course in the diet, the exclusion of everything 

 containing starch, which may be converted into sugar, will be bene- 

 ficial. I will read upon this subject a portion of an article by Prof. 

 Huxley, showing that the tendency of his mind is in the same direc- 

 tion that this association has been tending toward for the last year, 

 that many contagious diseases, and perhaps all, are the results of 

 minute organisms, animal or vegetable, which get into the system 

 and generate disease. 



Yeast. 

 By Professor T. H. Huxley, of London. 



It has been known, from time immemorial, that the sweet liquids 

 which may be obtained by expressing the juices of the fruits and 

 stems of various plants, or by steeping malted barley in hot water, 

 or by mixing honey with water, are liable to undergo a series of very 

 singular changes, if freely exposed to the air and left to themselves, 

 in warm weather. However clear and pellucid the liquid may have 

 been when first prepared, however carefully it may have been freed 

 from even the finest visible impurities, by straining and filtration, it 

 will not remain clear. After a time it will become cloudy and tur- 

 bid ; little bubbles will be seen rising to the surface, and their abund- 

 ance will increase until the liquid hisses as if it were simmering on the 

 fire. By degrees some of the solid particles which produce the tur- 

 bidity of the liquid collect at its surface into a scum, which is blown 

 up by the emerging air bubbles into a thick, foamy frolh. Another 

 moiety sinks to the bottom, and accumulates as a muddy sediment, 

 or " lees." 



When this action has continued for a certain time, with more or 

 less violence, it gradually moderates. The evolution of bubbles 

 slackens, and finally comes to an end ; scum and lees alike settle at 

 the bottom, and the fluid is once more clear and transparent. But it 

 has acquired properties of which no trace existed in the original 

 liquid. Instead of being a mere sweet fluid, mainly composed of 

 sugar and water, the sugar has more or less completely disappeared, 

 and it has acquired that peculiar smell and taste which we call 

 " spirituous." Instead of being devoid of any obvious effect upon 

 the animal economy, it has become possessed of a very wonderful 



