202 BACTERIA. 



growing in a fluid medium. When they were allowed to 

 dry, however, this did not appear to hold good to nearly the 

 same degree. 



These experiments are interesting in their bearing on the 

 outbreaks of typhoid fever at certain parts of the year, 

 especially in countries where the cold appears to be exceed- 

 ingly intense, and where one would naturally expect the 

 development of the bacilli to be interfered with, but where 

 as a matter of fact such is found not to be the case. 



Quite recently Cassedebat, examining the drinking water 

 supplied to Marseilles, which is a very hotbed of typhoid fever, 

 was not able to find the characteristic bacillus in any one of 

 250 cultivations made of seventy specimens of water, but 

 curiously enough he found three other bacilli which in many 

 respects resembled the true typhoid bacillus most remark- 

 ably, although they differed in certain essential character- 

 istics. He points out that they all grow in the phenic acid 

 gelatine, and he further states that several other organisms 

 offer quite as great resistance to this acid as the typhoid 

 bacillus itself. They all present clear spaces or deeply stained 

 masses of protoplasm which may easily be mistaken for spores, 

 but these, like those in the true typhoid bacillus in which as 

 we have seen similar bodies occur, are all killed at a tempera- 

 ture of a little over 45 C. The pseudo-bacilli are very im- 

 perfectly stained by Gram's method. They exhibit a lateral 

 and oscillatory motion as well as a forward motion. The 

 plate cultivations are so much alike, that unless all four can 

 be examined simultaneously, it is a very difficult matter to 

 distinguish one from the other ; their growths on potatoes, 

 in broth and in milk resemble one another in a most re- 

 markable manner, except that they develop with different 

 degrees of rapidity, and vary somewhat as regards the alkali- 

 nity and acidity of their products at the end of about thirty 

 days, and also as to the degree and time of appearance of 

 turbidity that is produced when these organisms grow in 

 broth. In consequence of these slight differences the use of 

 the various aniline staining reagents, added to such culture 

 media as broth or milk in which the colours undergo 

 changes under the different reactions, has been resorted to 

 and described by Cassedebat, who was able by their use 

 to distinguish one organism from the other. The ordinary 

 cultivation methods are quite sufficient to distinguish these 



