166 MICRO-OKGANISMS AND DISEASE. [CHAP. 



Thus also this third case of a transformation of a common 

 into a specific organism due to altered conditions of growth 

 falls to the ground. 



It might be now asked, how about those cases in which by 

 injection of very small quantities of putrid organic substances, 

 pyaemia or septicaemia, has been produced in rodents 1 Take 

 the case of Davaine's septicaemia in rabbits. This disease has 

 been produced in rabbits by Davaine, Coze and Feltz, and by 

 many other observers, by injecting into the subcutaneous tissue 

 of healthy rabbits small quantities of putrid ox's blood. The 

 rabbits die in the course of a day or two, and their blood is 

 found teeming with minute organisms, which prove to be 

 bacterium termo ; every drop of this blood possesses infective 

 properties ; when inoculated into a rabbit it produces septic- 

 aemia with precisely the same appearances as before. Pasteur 

 and Koch have succeeded in producing septicaemia in mice and 

 rabbits, and especially in guinea-pigs, by inoculating them 

 subcutaneously with garden earth or with putrid fluid. This 

 is Pasteur's septicaemia, or Koch's malignant oedema ; it is 

 characterised by oedema at the seat of inoculation, and spread- 

 ing hence in the subcutaneous tissue of the surrounding 

 parts. The animals die generally in twenty-four to seventy- 

 two hours. 



Koch has produced by injection of small quantities of 

 putrid fluids into the subcutaneous tissue of mice a peculiar 

 septicaemia ; the animals sometimes die in forty to sixty hours, 

 and the white corpuscles of the blood are found crowded with 

 exceedingly minute bacilli. Koch succeeded also in producing 

 a pyaemia in rabbits by injection of putrid fluids, and this 

 pyaemia is characterised by zooglcea of minute micrococci being 

 present in the blood-vessels. Further, a progressive necrosis 

 in mice by inoculating them with putrid fluids, the necrosis 

 being due to the growth of micrococci and spreading from the 

 seat of inoculation, and destroying as they spread all the 

 elements of the tissue. All these cases have been minutely 

 described by Koch in his classical work, Die Aetiologie der 

 Wundinfectionskranlchei ten, Leipzig, 1879. I have in addition 

 mentioned in Chapter VII. 13 a micrococcus causing abscess 

 and pyaemia in mice. 



Now do these cases prove that septic micro-organisms, living 

 and thriving in putrid organic fluids, can, when introduced 

 into the body of animals, owing to some peculiar unknown 

 condition, so change as to produce a fatal infectious disease 1 

 I must say, with Koch, who has very ably discussed all these 

 points, ' No.' Those organisms which are connected with the 



