574 Microscopic Organisms in Blood and their Relation to Disease, [part hi. 



bodies could be observed under suitable conditions. On careful examination each 

 " s[)ore " is seen to be an oval-shaped body embedded in a translucent substance which 

 appears to surround the former in a ring-like fashion, but is seen to be in reality 

 spherical, on being rolled over. This substance loses its spherical form and becomes 

 elongated at one end in the direction of a long axis of the contained " spore." The 

 latter remains at one end, and very soon the translucent tube assumes a filamentous aspect 

 and, contemporaneously, the "spore" becomes less refringent, pale and small, and 

 possibly breaks down into fragments, until it eventually disappears completely.* Dr. 

 Koch's figure (Fig. 41), representing the various stages of the supposed germination- 

 process, is reproduced. 



This interpretation of what occurs is made particularly important from the fact 

 that it has been resorted to very lately by M. Pasteur to account for the circumstance 

 that, although it has been proved, beyond all reasonable doubt, that splenic fever, 

 together with blood-bacilli, may be induced by inoculation with virus after the total 

 destruction of the filament- bacillus which the morbid material had contained, yet 

 because the " spores " remained (it would seem that they are considered nearly 



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Fig. 41. — Bacillus AntJiracis : Germination of Fig. 42. — Bacillm anthracis : Germination of 



the spores. (After Koch.) x 650 diam. the spores. (After Cohn.) x 1,650 diam. 



indestructible) the virus had retained its property— the " spores " in fact being the 

 virus. 



Professor Cohn favoured Dr. Koch with a sketch of the same developmental process 

 as seen under a higher power. This figure is also reproduced for purposes of comparison. 

 Koch suggests that probably the " spore " consists of a strongly refractive substance, 

 probably oil, which is enveloped by a thin layer of protoplasm — the latter being the 

 substance capable of germination, and the former, perhaps, serving as nourishment 

 during the germinating process. The foregoing, according to various writers, represents 

 the complete cycle of development undergone by Bacillus anthracis. 



Davaine, it will be recollected, had found that animals eating diseased tissues 

 mixed up with their food became themselves affected, and he believed that the spread 

 of the disease could thus to some extent be easily accounted for. Koch, on the 

 contrary, finds that animals very susceptible to infection by inoculation, such as mice 

 and rabbits, may devour such a mixture with impunity. Attempts to inoculate two 

 dogs, a partridge, and a sparrow, proved fruitless. 



 Loc. cit., p. 289. 



