188 MIOKOBES, FERMENTS, AND MOULDS. 



fever. In all these countries poverty, scarcity, and 

 famine appear to be the predisposing causes. In 

 this case, the presence of microbes in the human 

 blood has been established in the clearest and most 

 incontestable way. This discovery was made by 

 Virchow and Obermeier in 1868, but nothing was 

 published on the subject until 1873. 



The symptoms of the disease are very like those 

 of typhoid fever. The microbe, which may always 

 be found in the blood, and which characterizes the 

 disease, is a Spirillum or Spirochcete {8. Ohermeieri) ; 

 that is, a filamentous organism, twisted into several 

 spirals, and animated by very lively movements (Fig. 

 51, m, o). These spiriUa may be seen moving in 

 thousands among the blood-corpuscles, when these are 

 placed under the objective of the microscope. 



The difficulties experienced by the original 

 observers in their attempts to inoculate man or 

 animals with the disease, and the fact that in some 

 cases the microbes appear to be absent from the 

 blood of affected persons, have thrown some doubt 

 on the relation between the disease and its microbe. 

 This is because the conditions of the existence of 

 this plant in the system were not sufficiently con- 

 sidered. Albrecht has recently shown (1880) that 

 blood which apparently contains no spirilla will, if 

 kept in a culture-flask for some days, protected from 

 air-germs, become full of these organisms at the end 

 of that time, a proof of the pre-existence of the spores 



