ACTION OF LIGHT ON MICRO-ORGANISMS 363 



liis experiments were made with the sporeless bacilli 

 obtained from the blood of a rabbit dead of anthrax. 

 The effect of desiccation was first tried by introducing 

 single drops of anthrax blood into glass tubes, and 

 subsequently drying them. In some tubes the drop of 

 dried blood was preserved in a vacuum, whilst in others 

 the air was not removed. Such tubes were kept in the 

 dark, some in an incubator at 33 C., and some in a 

 cupboard at from 16 to 22 C, After definite lengths of 

 time had elapsed, nutritive bouillon was added to these 

 tubes, and they were placed in the incubator at 33 C. 

 to see if any growths would make their appearance. 

 The following results were obtained : 



ANTHRAX BACILLI. Desiccation Experiments Conducted 



in the Dark 



(1) Dried anthrax blood in contact with air, pre- 

 served in the dark at from 16-22 C. Maximum dura- 

 tion of life of the bacilli, fifty-seven days. The final 

 bouillon culture obtained in testing the vitality de- 

 veloped only after twenty-four hours. Inoculated into 

 a guinea-pig, it died of anthrax in thirty hours. No 

 attenuation of virulence observed. 



In vacuo under similar conditions, maximum dura- 

 tion of life of the bacilli forty-eight days. 



(2) Dried anthrax blood in contact with air, but 

 kept in the incubator at 33 C. Maximum duration of 

 life of the bacilli, forty-five days. The final bouillon 

 culture obtained developed only after three days. In- 

 oculated into a guinea-pig, it died of anthrax in thirty- 

 seven hours. 



In vacuo under similar conditions, maximum dura- 

 tion of life of the bacilli fifty days. Bouillon culture 

 inoculated into a guinea-pig killed it in thirty-six hours 

 of anthrax. 



