188 MICROBES, 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 Spirochate (S. Obermeiert) ; 
that is, a filamentous organism, twisted into several 
spirals, and animated by very lively movements (Fig. 
51, m, 0). These spirilla 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 
