172 DR. E. KLEIN. 



of the most prominent symptoms, e.g. inflammation of lung 

 and serous membranes, enlargement of inguinal, lumbar, 

 and bronchial lymphatic glands, haemorrhages in endocard 

 and muscle of the heart in pneumo-enteritis on the one 

 hand, and swelling and ulceration of ihe lymphatic glands 

 of the small intestine, swelling and inflammation of spleen 

 in real typhoid fever on the other hand. The resemblance 

 seems to be limited solely to the fact that in both diseases 

 there occurs ulceration in the intestine. But the distribu- 

 tion, the nature, and the development of these ulcerations 

 are totally difierent in the two diseases. 



Having said thus much as a prefatory explanation, I 

 proceed to state the results of the experiments.' 



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 di ' produce in- 

 fection. [And this same blood proved active after having 

 been kept sealed up in a capillary lube 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 lypmh 

 of the diseased peritoneum contains the virus in a very 

 active state. 



' In all my experiments of inoculation the materies morbi was used in 

 minimal doses, i.e. a drop of fluidmattcr, or in the case of solids a particle 

 of less than the size of a pin's head. In both cases the materies morbi 

 was diluted or suspended respectively in a few minims of boiled saline 

 solution of ^ per cent, in order to increase its bulk and thus to facilitate 

 its introduction. The inoculation was invariably carried out by injec- 

 tion into the subcutaneous tissue by means of a fine canula of a hypo- 

 dermic 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 ensure reliableresults (viz. that the disease in a 

 particular case was really a consequence of the inoculation and not of 

 infection tlirough other sources) care was taken that those who attended 

 the isolated animals were not the carriers of infection. 



