BACTERIA AS THE CAUSES OF DISEASE. 83 



suppuration, nor did it cause death : but if to this a quantity 

 of the micro-organisms were added, and the fluid was then 

 injected into dogs, these animals succumbed to a true pyaemia, 

 accompanied by the formation of abscesses, especially near 

 the points of inoculation. He showed that these organisms 

 were not present in the normal healthy blood ; he also, 

 by means of ingenious apparatus, which he contrived or 

 modified, was able to observe the actual multiplication of the 

 micrococci under the microscope. He introduced the method 

 of fractional cultivation, but not in the complete form in 

 which it was afterwards used by Lister and Pasteur, as he 

 relied on the more vigorous growth of a certain organism 

 that was placed in a special fluid and under special con- 

 ditions, rather than on the dilution and isolation of individual 

 organisms in small drops of fluid. Klebs was, however, able, 

 by his biological method, to obtain comparatively pure culti- 

 vations of several bacteria and micrococci, and he was the 

 first to distinguish the division going on in various planes. 



Klebs' anatomical investigations were confirmed by numerous observers, 

 Birch-Hirschfeld, Heiberg, Orth, and Hueter, the last of whom tried to 

 build up a system of pathology on the basis of the researches that had 

 already been carried out ; these, however, afforded very incomplete data on 

 which to work. Pyaemia was, he considered, the result of the invasion of 

 the tissues by micrococci, with the formation of little plugs in the vessels, 

 around which abscesses were developed ; septicaemia was a general poison- 

 ing by absorption from a localized formation of bacteria in the body ; and a 

 third form, which he looked upon as putrid poisoning, was the result of the 

 absorption of poisonous matter formed by vibriones existing outside the 

 body. The only difficulty in the matter was that the same organism 

 appeared to produce very different conditions, such as pyaemia, septi- 

 caemia, puerperal fever, pyelo-nephritis, typhoid fever, phthisis, small- 

 pox, diphtheria, cholera, rinderpest, whilst even in the healthy body 

 organisms were sometimes found, especially in certain positions, a fact 

 which at that time was not reconcilable with the various theories that had 

 been advanced. Another objection stated was that as the bodies of patients 

 who had died of pyaemia and septicaemia putrefied rapidly, they formed an 

 especially good medium in which innocuous organisms might grow, and it 

 was maintained that organisms were found in such bodies after death, 

 because of the special suitability of the soil for their growth, and that they 

 were therefore probably rather to be looked upon as accidental concomitants 

 and consequences than as essential factors in the production of disease. 



There now also appeared great activity in the French 

 school : Pasteur had shown that most of the processes of 

 putrefaction were due to the presence of motile, anaerobic 

 vibriones, whilst Davaine had observed only non-motile rod- 



