CHARACTERS OF THE SPIRILLUM 439 



are closely similar, if not identical. As a matter of convenience, 

 and in accordance with the history of the investigations, we shall 

 give the chief facts regarding these diseases separately. It has 

 also been shown that spirillar diseases or " spirilloses," as they 

 are called, are widespread in the animal kingdom. Such 

 infections have been described in geese by SacharofF, in fowls by 

 Marchoux 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. 



The work of Schaudinn(v. p. 548) has led to these spirochsete 

 being regarded by various authorities as members of the protozoal 

 group. As, however, 

 longitudinal division has 

 not been satisfactorily 

 observed and no cycle of 

 development has been 

 determined amongst them, 

 we are not justified at 

 present in removing them 

 from the class of bacteria. 



Characters of the 

 Spirillum. The organ- 

 isms as seen in the blood 

 during the fever are deli- 

 cate spiral filaments which 

 have a length of from two 

 to six times the diameter 

 of a red blood corpuscle. Fia 149. Spirilla of relapsing fever in 

 They are, however, exceed- human blood. Film preparation. (After 

 ingly thin, their thickness Koch.) x about 1000. 

 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 

 spirilla, and their extremities are finely pointed (Fig. 149). 

 There are often to be seen in the spirals, portions which are 

 thinner and less deeply stained than the rest, and which suggest 

 the occurrence of transverse division. 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. 

 Novy and Knapp have found that there is a single flagellum at 

 one end of the organism. 



They stain with watery solutions of the basic aniline dyes, 



