ACTION OF LIGHT ON MICRO-OEGANISMS 381 



the above results have only reference to the presence 

 or abstoce of anthrax as revealed by cultivation, but 

 experiments were also made on the virulence of these 

 waters which had been exposed to direct insolation. 

 Thus :— 



Animal Experiment. — On November 2, 1892, 1 c.c. 

 of the water from the flask ' 4 I, Thames water, unfil- 

 tered, and infected with anthrax on March 18, 1892, 

 exposed to 151 hours' sunshine,' was subcutaneously in- 

 jected into a white mouse. The mouse remained alive. 



Animal Experiment. — On November 2, 1892, 1 c.c. of 

 the water from flask ' 4 I, Thames water, steam-sterilised, 

 and infected with anthrax on March 18, 1892, exposed 

 to 151 hours' sunshine,' was subcutaneously injected 

 into a white mouse. The mouse remained alive. 



Animal Experiment. — On November 2, 1892, 1 c.c. 

 of the water from flask " 4 I, Thames water, porcelain- 

 filtered, and infected with anthrax on March 18, 1892, 

 exposed to 151 hours' sunshine,' was subcutaneously 

 iajected into a white mouse. The mouse remained 

 alive. 



Thus, in all three cases, the water was non-virulent 

 when injected to the amount of 1 c.c. It was, however, 

 obviously not to be necessarily concluded that the an- 

 thrax had become absolutely extinct in these waters, 

 and in order to put this point to the test the flasks in 

 question were each treated with 5 c.c. of sterile broth 

 and incubated at 37° C, after which the following 

 further experiments were made : — 



Animal Experiment. — On November 9, 1892, 0'5 c.c. 

 of the water (to which broth was added on November 7, 

 1892) from flask ' 4 I, Thames water, unfiltered, and 

 infecte,d with anthrax on M^rch 18, 1892, exposed to 

 151 hours' sunshine,' was subcutaneously injected into 

 a white mouse. The mouse remained alive. 



