68 BACTERIA IN DAILY LIFE 



pensable adjuncts, and by their means new sub- 

 stances have been prepared and fresh contributions 

 made to the science of chemistry. 



Momont is not able to give any satisfactory 

 explanation of this different behaviour of the 

 anthrax bacilli in these two media, but goes on 

 to show that yet another factor plays an impor- 

 tant part during insolation. 



In the above experiments air was allowed to 

 gain access to the vessels containing the broth, 

 but if the precaution be taken of first removing 

 the air and then exposing them to the sunshine, 

 a very different result was obtained, for instead 

 of the anthrax bacilli dying in from two to two 

 and a half hours, they were found to be still 

 alive after fifty hours' insolation. There appears, 

 therefore, to be no doubt that sunshine in some 

 way or other endows atmospheric oxygen with 

 destructive power over the living protoplasm 

 of the bacterial cells ; indeed, there is consider- 

 able reason to believe that the bactericidal effect 

 is due to the generation of peroxide of hydrogen, 

 which is well known to possess powerfully anti- 

 septic properties. 



Numerous investigations have been also made 

 to determine whether all the rays of the spectrum 

 are equally responsible for the bactericidal action 

 of light. 



