QUALITATIVE BACTERIOLOGICAL ANALYSIS. 209 



bacilli in water have become adapted to a comparatively low 

 temperature, and incubation at 37 C. may be inimical to them. 

 Remy stated that typhoid bacilli isolated from a stool and kept 

 at the room temperature of 25 to 30 C. did not develop well 

 in broth at 37 C., but grew vigorously in broth kept at 25 to 

 30 C. The pernicious influence of carbolic acid on weakened 

 forms of the typhoid bacillus is undoubted, and many bacteri- 

 ologists at the present day have abandoned the use of carbolised 

 media and prefer to make a large number of plates with 

 ordinary gelatine. By employing a small quantity of water, 

 diluted if necessary, for each plate, they hope to obtain com- 

 paratively few colonies, and so give the typhoid bacillus time to 

 develop without the risk of being crowded out by liquefying 



EXPERIMENTAL RESEARCHES ON THE DURATION OF LIFE OF 

 THE B. TYPHOSUS IN WATER, SEWAGE, ETC. 



Kraus introduced a large number of typhoid bacilli into three 

 samples of unsterilised water, one being a pure pipe supply and 

 the other two well-waters ; the bacilli disappeared between the 

 fifth and seventh day in all three samples. Hueppe repeated 

 Kraus's experiments and obtained the same results. Karlinski 

 introduced 30,000 typhoid bacilli into the Innsbruck water, and 

 found that after seven days they had completely disappeared. 

 Karlinski also placed typhoid dejecta, containing typhoid bacilli, 

 in a cistern filled with river arid rain water. Three experiments 

 were made, and in all of them the B. typhosus could not be 

 found after the third day. Bobrow studied the duration of life 

 of the B. typhosus in a well-water containing 15,000 water- 

 organisms per c.c. ; the typhoid bacillus could not be isolated 

 after eight days. Hueppe introduced typhoid bacilli into un- 

 sterilised well-water kept at 16 to 20 C. ; out often experiments 

 he found the typhoid bacilli had disappeared after five days on 

 four occasions, after ten days on five occasions, and in one case 

 they appeared to live up to the thirtieth day. Frankland 

 made simultaneous experiments on water derived from the 

 River Thames, Loch Katrine, and a deep well in the chalk. 

 The same amount of culture was introduced into the three 

 specimens. In the Thames water the B. typhosus could not 



