422 BIOLOGY OF THE LABORATORY MOUSE 



were noted even in those animals in which a fatal infection with the trypan- 

 osomes subsequently developed. Inoculation of rats produced an infec- 

 tion of varying severity, but not all rats were susceptible. The organism 

 was cultivated in Noguchi's medium (184), and was termed "virus 

 spontane." A second strain of bartonella, termed "virus provoque," was 

 obtained following splenectomy of normal mice. The clinical course of the 

 two infections was similar, and no morphological differences were noted in 

 the two strains. Other dift'erences were described, however. The "virus 

 provoque " was not cultivated. It did not infect normal mice (non-splenec- 

 tomized) or splenectomized mice which had recovered from the homologous 

 infection, although the latter animals were susceptible to the "virus spon- 

 tane." Mice, recovered from the "virus spontane," acquired the "virus 

 provoque" after spelenectomy without alteration in the incubation period 

 or duration of the infection. On the basis of these data, the two strains 

 were considered to be different immunologically. 



Evaluation of this work is difficult. The possibility exists that the 

 "virus spontane" may originally have been derived from the rat. Normal 

 mice are susceptible to Bartonella muris of the rat (238, i), and although 

 many authors (331) consider the rat and mouse strains to be identical, 

 definite differences have been reported (238, 167). In favor of the mouse 

 origin of the "virus spontane" is the fact that a similar strain of high 

 virulence was obtained from a splenectomized mouse having a mixed infec- 

 tion with bartonella and Eperythrozoon coccoides (157, 158). Kikuth (121), 

 however, encountered a similar mixed infection but was able to transmit 

 only the eperythrozoon to other splenectomized mice. 



As already mentioned, Bartonella muris of the rat may be transmitted 

 to mice by inoculation of infected rats' blood. Although many animals 

 show no signs of infection (122), a fatal anemia may develop both in normal 

 and in splenectomized animals (238, i, 2, 239, 167, 3). Repeated passage of 

 the organism in young normal mice may apparently increase its virulence 

 until most of the animals succumb from the infection (i). In such animals 

 all the erythrocytes may be infected by the fourth or fifth day and the num- 

 ber of red blood cells may fall from 9,000,000 per cu. mm. at the time of 

 infection to 1,000,000 per cu. mm. at the time of death on the fifth or 

 seventh day. Hemoglobinuria, common in rats, rarely occurs in mice. 

 In animals which recover, the destruction of the organisms is sudden, con- 

 stituting a crisis in which the number of infected cells falls from 100 per 

 cent to less than i per cent within 24 hours. The spleen is uniformly 

 enlarged (three to four times normal size) , and in recovered animals there is 



