STUDIES ON FERMENTATION. 303 



lactate of lime and phosphates, which we had impregnated on 

 the 9th with two drops of a liquid in butyric fermentation. 

 In the course of a few days fermentation declared itself : on 

 the 16th it was in progress, but feebly ; on the 18th it was 

 active ; on the 30th it was very active. On June 1st it yielded 

 hourly 35 c.c. (2'3 cubic inches) of gas, containing ten per cent, 

 of hydrogen. On the 2nd we began the study of the action of 

 air on the vibrios of this fermentation. To do this we cut off 

 the delivery-tube on a level with its point of junction to the 

 flask, then with a 50 c.c. pipette we took out that quantity 

 (If fl. oz.) of liquid which was, of course, replaced at once by 

 air. We then reversed the flask with the opening under 

 the mercury, and shook it every ten minutes for more than an 

 hour. Wishing to make sure, to begin with, that the oxygen 

 had been absorbed, we connected under the mercury the beak 

 of the flask by means of a thin india-rubber tube filled with 

 w^ater, with a small flask, the neck of which had been drawn 

 out, and was filled with water ; we then raised the large flask 

 with the smaller kept above it. A Mohr's clip, which closed the 

 india-rubber tube, and which we then opened, permitted the 

 water contained in the small flask to pass into the large one, 

 whilst the gas, on the contrary, passed upwards from the large 

 flask into the small one. We analyzed the gas immediately, 

 and found that, allowing for carbonic acid and hydrogen, it 

 did not contain more than 14*2 per cent, of oxygen, which 

 corresponds to an absorption of 6'6 c.c, or of 3*3 c.c. (0'2 cubic 

 inch) of oxygen for the 50 c.c. (3"05 cubic inches) of air 

 employed. Lastly, we again established connection by an india- 

 rubber tube between the flasks, after having seen by micro- 

 scopical examination that the movements of the vibrios were 

 very languid. Fermentation had become less vigorous without 

 having actually ceased, no doubt because some portions of the 

 liquid had not been brought into contact with the atmospheric 

 oxygen, in spite of the prolonged shaking that the flask had 

 undergone after the introduction of the air. Whatever the 

 cause might have been, the significance of the phenomenon is 



