TYPHUS FEVER 695 



well, may really suffer from a slight rise of temperature. This 

 condition is probably an abortive attack of the fever, as the 

 blood in such cases is infective for monkeys. These abortive 

 cases may play a part in the dissemination of an epidemic, and 

 also, it is possible, in the recurrent outbreaks of the disease in 

 cities in which otherwise there is no evidence of typhus fever 

 being endemic in its usual form. Nicolle's results have been 

 confirmed in America by Anderson and Goldberger and by 

 Ricketts and Wilder. These observers in the first instance were 

 dealing with a fever in Mexico known as tabardillo. Anderson 

 and Goldberger, however, also worked with cases of a disease 

 occurring in New York (described by Brill), which were un- 

 doubtedly a mild type of typhus fever imported from Europe, 

 and they proved experimentally the identity of the two con- 

 ditions. Nicolle observed that as in the case of man, when an 

 experimental animal passes successfully through an attack of 

 the disease it becomes immune. Although the serum of both 

 men and animals during convalescence possesses slight viricidal 

 properties, this rapidly disappears. Nicolle and Blaizot by 

 immunising the horse with bruised supra-renals and spleens 

 of infected guinea-pigs have produced a serum which has 

 protective and curative effects in man. On the other hand, 

 Blanc used the infected guinea-pig's blood sterilised at 55° C. 

 as a prophylactic and therapeutic vaccine. 



Nicolle has not advanced any views with regard to the nature 

 of this infective agent beyond the fact that it is destroyed by 

 a short exposure at from 50° to 55° C. He adduced some 

 observations pointing to its being filterable, but these have not 

 been confirmed. Ricketts and Wilde described in the blood of 

 typhus patients minute rod-shaped bodies with polar staining. 

 This observation has been confirmed, especially in lice, by 

 Prowazek, Rocha-Lima, Topfer, and Schussler and others. The 

 bodies vary in size, the smallest being cocciform and less than 

 the m. melitensis, or elliptical, with one end pointed ; larger forms 

 also occur,— rod-shaped, with polar staining and an unstained 

 central part, — some say the ends are surrdunded by a pale 

 capsule. In the louse they may occur amongst the debris of 

 red blood cells in the stomach, but are most marked in the 

 epithelial cells of the stomach and intestine, and in the salivary 

 glands. According to present results, like appearances have not 

 been found in control lice which have not been fed on typhus 

 patients. Notwithstanding their likeness to coccobacilli, Rocha- 

 Lima inclines to look on these bodies as protozoa, and suggests 

 for them the name Rickettsia prowazehi. There is general 



