BY R. GREIG SMITH. 651 



cause of the trouble or disease. Once the cause is obtained, 

 experiment will soon suggest a cure. There is always the 

 possibility, however, that the turbidity might not be due to the 

 bodies of living organisms, but to the action of enzymes derived 

 either from the original grapes or from the yeasts that played a 

 part in the fermentation. But it is unlikely that an enzyme 

 would coagulate some of the soluble constituents at so late a stage 

 in the history of the wine. 



Wortmann (Referat in Centralblatt fur Bakt., ii. Abt., vi., 298) 

 traced a turbidity of wine, which set in after the wine had been 

 bottled, to the gradual disintegration of yeast cells. Sometimes, 

 owing to a variety of causes, such as low acidity or too high a 

 temperature during fermentation, wine may not be completely 

 fermented. It is in such cases that slowly growing yeast cells 

 may be present in greater amount than in the case of thoroughly 

 fermented wines. Wortmann apparently came to his conclusion 

 from a microscopical examination of the wine alone. Had I 

 depended solely upon microscopical observations of the Chablis 

 when the turbidity had made itself evident, I might have come 

 to the same conclusion, for thin films of the wine showed nothing 

 but what might be particles of organic matter in Brownian move- 

 ment. However, to diagnose the exciting cause of any disease 

 of food or animal from simple microscopical examination alone does 

 not generally recommend itself to the zymo-technologist or the 

 bacteriologist. 



In separating the living cells ordinary nutrient agar was first 

 used, and a series of plates were prepared from infected tubes of 

 the molten medium. Although this medium favours the growth 

 of most bacteria, yet yeasts can obtain enough nutriment from it 

 to grow as small colonies. It is, therefore, an excellent medium 

 for finding out what micro-organisms are probably present in any 

 substance. The plates in due course grew several kinds of colonies, 

 among which were a common mould, Penicillium glaucum, and 

 two bacteria, Sarcina lutea and Bacillus subtilis. Besides these 

 there were a number of yeast colonies, and to obtain more 



