340 BULLETIN No. 161 [November, 



DURATION OF LIFE OF TUBERCLE BACIL/LJ IN WATER 



PURPOSE AND ^ ne purpose of these tests was primarily to deter- 

 PLAN OF TESTS mine how long bovine tubercle bacilli will live in 

 a watering tank such as is found on the average 

 stock farm in Illinois. In connection with this work it was desired 

 to test the length of time human tubercle bacilli will live in drink- 

 ing water. With this in view experiments were planned and car- 

 ried out with tubercle bacilli from the following sources : 



1. Pure cultures, Series i. 



2. Pure cultures, Series 2. 



3. The diseased tissues of a tuberculous guinea pig. 



4. Tuberculous sputum. 



Series i. Pure Cultures 



CULTURES The bovine culture was the same as that used in 



the cow manure which was exposed to weather 

 conditions. The human culture was taken from the tuberculous 

 glands of the neck of a patient from the Burnham hospital and iso- 

 lated in this laboratory. The tissues were received May 25, 1910. A 

 pure culture was obtained by inoculating a guinea pig and cultur- 

 ing the diseased tissues of the guinea pig. This culture, which is 

 typical for the human type, has since been kept upon glycerine agar. 



SAMPLES OF The sam pl e f water used to make the emulsion 

 WATER for exposing the bovine tubercle bacilli was ob- 



tained from the large watering tank used to water 

 the dairy cattle of this station. This tank is 2^x4x10 feet, and 

 is supplied with running water. A considerable amount of spiro- 

 gyra and various kinds of smaller green algae was floating in the 

 tank. Diatoms were also abundant. A green scum covered a 

 large portion of the surface of the water. The sample was ob- 

 tained in a 500 cc., sterile, cotton-stoppered flask. The water in 

 the tank was slightly agitated with a stick about as much as it 

 was thought the cattle would stir the water by drinking. The 

 mouth of the flask was plunged under about six inches and then 

 allowed to fill. The sample was at once taken to the laboratory 

 and the emulsion prepared that same afternoon. The spirogyra 

 died soon after the emulsion was made, but the diatoms and the 

 smaller green algae, as well as numerous bacteria, were present at 

 the conclusion of the experiment December 5, 1911, 586 days after 

 the experiment started. The sample of water used to make the emul- 

 sion with the pure culture of human tubercle bacilli was taken from 

 the tap water of the bacteriological laboratory. There were at the 



