1878.] 



Etiology of Infectious Diseases. 



103 



The experiments refer to the following series : — 



1. Experiments showing that the fresh blood of diseased animals 

 does not, as a rule, contain the virus, as it fails to produce the disease 

 when introduced into a healthy animal. 



Four animals were inoculated (at different times) with fresh blood 

 of diseased animals. They remained healthy. When subsequently 

 inoculated with virus- containing matter, they became smitten with 

 the disease. 



In a fifth instance, however, fresh blood did produce infection. 

 [And this same blood proved active after having been kept sealed up 

 in a capillary tube for several weeks.] This blood was obtained from 

 a very severe case with copious peritoneal exudation, in which were 

 found peculiar abnormally large coarsely granular cells; the same 

 cells were also present in the blood ; so that it appears probable that 

 the blood became charged, by absorption during life, with matter 

 from the peritoneal exudation. This latter always contains the virus 

 in an active state. 



2. Experiments showing that fluid as well as solid lymph of the 

 diseased peritoneum contains the virus in a very active state. 



Six successful inoculations with fluid peritoneal exudation. 



There is no difference of activity to be noticed between fresh 

 exudation and one that had been kept sealed up in a capillary tube 

 for several weeks. 



Solid lymph obtained from the peritoneal cavity of diseased animals, 

 having been dried at a temperature of about 38° C, proves very 

 active. 



3. Experiments showing that parts of the diseased lung, ulcerated 

 intestine, and also diseased spleen, contain the virus in an active state. 

 Diseased parts of lung or intestine, that were dried at a temperature 

 of about 38° C, retain their virulence unaltered. 



In all cases of pneumo-enteritis the trachea as well as the bronchi 

 contain frothy blood- containing mucous matter, possessed of infectious 

 property. It must be, therefore, supposed that the breath of a 

 diseased animal is charged with the poison. On account of the 

 diseased state of the intestine also, the dung is to be regarded as in- 

 fectious. 



4. Experiments showing that infection is produced by cohabitation 



crease its bulk and thus to facilitate its introduction. The inoculation was invariably 

 carried out by injection into the subcutaneous tissue by means of a fine canula of 

 a hypodermic syringe, necessary care being taken that this had been previously 

 thoroughly cleaned and disinfected. After and before inoculation the animals have 

 always been kept isolated and in clean and disinfected places. In order to insure 

 reliable results (viz., that the disease in a particular case was really a consequence 

 of the inoculation and not of infection through other sources) care was taken that 

 those who attended the isolated animals were not the carriers of infection. 



