CHAKACTEKS OF THE SPIROCHETE 507 



that its presence in the blood had a definite relation to the time 

 of the fever, as the organism rapidly disappeared about the time 

 of the crisis, and reappeared when a relapse occurred. His 

 observations were fully confirmed, and his views as to its causal 

 relationship to the disease have been established as correct. 



Within recent years relapsing fever has been carefully studied 

 in different parts of the world, and the relationships of the 

 organisms have been the subject of much investigation and 

 discussion. This question will be referred to again below. 

 It has also been shown that the so-called " tick fever " prevalent 

 in Africa is due to a spirochete of closely similar character, 

 and results of the highest importance have been established 

 with regard to the part played by ticks in the transmission 

 of the disease. As a matter of convenience, we shall give 

 the chief facts regarding these diseases separately. It has 

 also been shown that spirochaetal diseases or "spirilloses," as 

 they are called, are widespread amongst vertebrates ; they 

 have been described, for example, in geese by Sacharoff, in fowls 

 by Marchpux and Salimbeni, in oxen and sheep by Theiler, and 

 in bats by Nicolle and Comte, and it is interesting to note that in 

 the case of the spirilloses of oxen and fowls the infection is 

 transmissible by means of ticks. 



Characters of the Spirochsete of Relapsing Fever. — The 

 organisms as seen in the blood during the fever are delicate 

 spiral filaments which have a length of from two to six times 

 the diameter of a red blood corpuscle. They are, however, 

 exceedingly thin, their thickness being much less than that of 

 the cholera spirillum. They show several regular sharp curves 

 or windings, of number varying according to the length of the 

 organisms, and their extremities are finely pointed (Fig. 152). 

 They are actively motile, and may be seen moving quickly across 

 the microscopic field with a peculiar movement which is partly 

 twisting and partly undulatory, and disturbing the blood corpuscles 

 in their course. There are often to be seen in the spirals, portions 

 which ar,e thinner and less deeply stained than the rest, and 

 which suggest the occurrence of transverse division. Fantham 

 and Porter find that the sp. obermeieri and sp. duttoni multiply 

 both by longitudinal and by transverse division, the former 

 occurring especially during the onset of the fever. 



They stain with watery solutions of the basic aniline dyes, 

 though somewhat faintly, and are best coloured by the 

 Eomanowsky method or one of its modifications. When thus 

 stained they usually have a uniform appearance throughout, or 

 may be slightly granular at places, but they show no division 



