3O4 MANUAL OF BACTERIOLOGY. 



The typhoid bacillus is killed at 60 C. in ten minutes. 

 It resists drying well. It can survive in soil and sewage a 

 long time. 



For a comparison of the properties of the typhoid bacillus 

 and the colon bacillus see the latter. 



Concerning the detection of the typhoid bacillus in 

 water see page 142. 



A new medium has been suggested by Hiss 1 for the isolation of the 

 typhoid bacillus. It consists of gelatin and agar, beef-extract, sodium 

 chloride and dextrose, and is given a slightly acid reaction. These sub- 

 stances are used in different proportions for plate- and for tube-cul- 

 tures. This medium is of a semi-solid character, and makes use of the 

 great motility of the typhoid bacillus in producing a uniform clouding 

 of the medium in tubes, with the absence of a gas formation; while 

 in plate-cultures the colonies exhibit peculiar filamentous outgrowths. 

 It is claimed that it can be determined whether organisms are typhoid 

 bacilli or not after thirty-six hours in the incubator. 



Other special media for the identification of the typhoid bacillus have 

 been devised by Eisner, Stoddart, by Capaldi and Proskauer, and bj 

 Piorkowski. 2 The medium of Stoddart is based upon principles similar 

 to those applied in the medium of Hiss. 



M. W. Richardson has devised an application of the serum-test to 

 plate-colonies suspected of containing typhoid bacilli. If a typhoid colony 

 be torn with a needle, under moderate magnification " a seething motion 

 resembling much the appearance of a swarm of bees " may be seen. 

 This appearance is due to the motility of the bacteria. If such a colony 

 be touched with a small quantity of blood-serum from a case of typhoid 

 fever, the motion is said to cease instantly and almost absolutely. 

 Colonies of other motile bacteria do not undergo a corresponding loss 

 of motility. 



THE SERUM-TEST FOR TYPHOID FEVER. 3 

 When a small quantity of a culture of typhoid bacilli is 

 mixed with a little blood-serum derived from a case of ty- 



1 Journal Medical Research, Vol. VIII., 1002. 



"Eisner, Zcitschrift f. Hygiene, Bd. XXL, 1895, p. 25; Stoddart. 

 Journal of Pathology and Bacteriology, Vol. IV., p. 429, 1897; Capaldi 

 and Proskauer, Zcitschrift fiir Hygiene, etc., Bd. XXIII. , p. 452, 1896; 

 Piorkowski, Berliner klinischc irochcnschrift, 1899, p. 145. 



3 This test is often known as the " Widal reaction." For a history and 

 general discussion of the subject see Durham, Journal of Experimental 

 Medicine, Vol. V., p. 353. 



