'iO STUDIES ON FEUME STATION. 



say, for instance, that which is known in Paris as Tourtel's, 

 Griiber's, or Dreher's, from the name of the brewer who manu- 

 factures it. Place some of these bottles in a hot-water bath and 

 raise the temperature to about 60° C. (140° F.). Permit them to 

 coof and then place them by the side of the other bottles that 

 have not been heated. In every case, especially if we conduct this 

 experiment in summer, we shall find that in the course of a few 

 weeks — the length of time varying according to the tempera- 

 ture and the quality of the beer — all the bottles which have not 

 been heated will have become diseased, in some cases even to 

 the extent of being undrinkable. Let us next examine, by 

 way of comparison, the deposits in the heated and non-heated 

 bottles. We shall find associated with the pure alcoholic fer- 

 ment other organisms, filiform and for the most part very slender, 

 and either simple or articulated, as represented in Plate IT., the 

 design of which is taken from actual deposits occurring iu beer 

 that had been kept for some time at the ordinary'' temperature. 

 A number of bottles of beer which had been heated on October 

 8th, 1871, were compared with those of an equal number of 

 bottles of the same beer which had not been heated. The 

 examinaticm took place on July 27th, 1872. The beer, which 

 had been heated to 55° C. (131° F.), was remarkably sound, 

 well flavoured, and still in a state of fermentation. As a matter 

 of fact, Ave have proved by exact experiments that alcoholic 

 ferments, heated in beer, can endure a temperature of 55° C. 

 (131° F.), without losing the power of germination ; but the 

 action is rendered somewhat more difficult and slower. Diseased 

 ferments, however, existing in the same medium, perish at this 

 temperature, as they do in the case of wine. The beer which 

 had not been heated, had undergone changes which rendered it 

 quite undrinkable. Its acidity, due to volatile acids, was higher 

 than that of the other beer in the proportion of 5 to 1. The 

 beer which had been heated contained A per cent, of alcohol 

 more than the other. 



The deposits in the heated bottles also showed filaments of 

 disease, but in such rninutc quantity that it was necessary to 



