290 FRAGMENTS OF SCIENCE 



be enclosed in the film, round it the bacteria will pirou- 

 ette and wabble until its oxygen has been absorbed, after 

 which all their motions cease. Precisely the reverse of all 

 this occurs with the vibrios of butyric acid. In their case 

 it is the peripheral organisms that are first killed, the cen- 

 tral ones remaining vigorous while ringed by a zone of 

 dead. Pasteur, moreover, filled two vessels with a liquid 

 containing these vibrios; through one vessel he led air, 

 and killed its vibrios in half an hour; through the other 

 he led carbonic acid, and after three hours found the vib- 

 rios fully active. It was while observing these differences 

 of deportment fifteen years ago that the thought of life 

 without air, and its bearing upon the theory of fermenta- 

 tion, flashed upon the mind of this admirable investigator. 



We now approach an aspect of this question which con- 

 cerns us still more closely, and will be best illustrated 

 by an actual fact. A few years ago I was bathing in an 

 Alpine stream, and returning to my clothes from the cas- 

 cade which had been my shower-bath, I slipped upon a 

 block of granite, the sharp crystals of which stamped them- 

 selves into my naked shin. The wound was an awkward 

 one, but being in vigorous health at the time, I hoped 

 for a speedy recovery. Dipping a clean pocket-handker- 

 chief into the stream, I wrapped it round the wound, 

 limped home, and remained for four or five days quietly 

 in bed. There was no pain, and at the end of this time 

 I thought myself quite fit to quit my room. The wound, 

 when uncovered, was found perfectly clean, uninflamed, 

 and entirely free from matter. Placing over it a bit of 

 goldbeater 's-skin, I walked about all day. Toward even- 

 ing itching and heat were felt; a large accumulation of 



