94 



ATLAS OF BACTERIOLOGY. 



potato) which are drying slowly at the temperature 

 of the room, is often astonishingly long, even when 

 this cannot be attributed to the development of endo- 

 spores. Even after the lapse of a year it is found 

 occasionally that such a shrivelled remnant of a cul- 

 ture furnishes the most beautiful cultures in bouillon. 



The question has often been investigated and with 

 very contradictory results as to the length of the time 

 during which bacteria free from spores, which have 

 dried upon pieces of glass or threads of silk, may 

 remain alive. We know now that this is influenced 

 by numerous factors. An idea of their viability is 

 furnished by the following table of Sirena and Alessi 

 (C. B., XL, 484). 



In bouillon cultures free from spores or in watery 

 deposits of bacteria silk threads were dipped, and 

 part of them were placed in test tubes one-third full 

 of sulphuric acid or calcium chloride, part were al- 

 lowed to dry in the open air under various conditions. 



PERIOD AT WHICH DEATH OCCURRED 

 (IN DAYS). 



Cholera vibriones are especially well known for 

 their slight power of resistance to desiccation. Ex- 



