TYPHOID FEVER. 469 



The resisting powers of the organism have already 

 been described as great. It can grow well at the room- 

 temperatnre. The thermal death-point is given by Stern- 

 berg as 6o° C. The bacilli can, according to Klemperer 

 and Levy, 1 remain vital for three months in distilled 

 water, though in ordinary water the commoner and more 

 vigorous saprophytes outgrow them and cause their dis- 

 appearance in a few days. When buried in the upper 

 layers of the soil the bacilli retain their vitality for nearly 

 six months. Robertson 2 found that when planted in 

 soil and occasionally fed by pouring bouillon upon the 

 surface, the typhoid bacillus maintained its vitality for 

 twelve months. He suggests that it may do the same 

 in connection with leaky drains. 



Cold has no effect upon typhoid bacilli, for freezing 

 and thawing several times are without injury to them. 

 They have been found to remain alive upon linen for 

 from sixty to seventy-two days, and upon buckskin for 

 from eighty to eighty-five days. Sternberg has succeeded 

 in keeping hermetically sealed bouillon cultures alive for 

 more than a year. In the presence of chemical agents 

 the bacillus is also able to retain its vitality, o. 1 to 0.2, 

 per cent, of carbolic acid added to the culture-media 

 being without effect upon its growth. At one time the 

 tolerance to carbolic acid was thought to be character- 

 istic, but it is now known to be shared by other bacteria. 

 The bacilli seem to be killed in a short time by thorough 

 drying. 



The bacillus is best secured in pure culture, either 

 from an enlarged lymphatic gland or from the splenic 

 pulp of a case of typhoid. To secure the bacillus in this 

 way the autopsy should be made as soon after death as 

 possible, lest the bacillus coli invade the tissue. 



Cultures of the typhoid bacillus may be obtained, but 

 with difficulty, from the alvine discharges of typhoid 

 patients. In examining this material, however, it must 



1 Clinical Bacteriology. 



* Brit. Med. Jour., Jan. 8, 1898. 



