277 



The kind of bloodvessel made no difference. Arteriae, venae, 

 and capillaries, they might come from the liver, the mesenterium, 

 or the spleen, they all brought on the same effect. 



The time wanted for the killing of the bacteria proved very 

 different in the case of naturally immune, and immunised 

 animals. One strain of white rats proved remarkably resistant 

 against pneumococcus-infections. When pneumococci after my 

 method were brought into the empty vessels, they disappeared 

 totally within a few hours. After 8, 16, and 24 hours they 

 remained invisible. But then a remarkable feat was observed. 

 After 36 hours the tissues have started autolysis. The nuclei 

 lose their sharp contours and staining qualities, the cells are 

 loosened. And then the pneumococci appear and grow into 

 colonies. The course of events probably is this : in the beginning 

 the endothelium killed the greater part of the pneumococci. A 

 few escaped and these, after waiting until by autolysis the 

 hostile functions of the endothelium had disappeared, made use 

 of the new circumstances and started growing. The absence of 

 capsulae in these colonies is to be explained by these conditions. 



The second method, of much simpler design, presented the 

 same results. Here only strepto- and staphylococci were used. 

 Experimental animals, normal, septicaemic, and immunised, 

 were bled to death. Then several bloodvessels were prepared 

 and cut open longitudinally. These vessels were then washed 

 in salt water and placed into a testtube containing melted agar, 

 (for streptococci bloodagar) of 40°. 



A small quantity of the bacteria corresponding with those 

 used in connection with the animal, was well mixed with the 

 agar. Then the agar was cooled down and the testtubes brought 

 into the incubator. Again after intervals of 8 hours pieces were 

 cut out, in the form of bloodvessels surrounded by a quantity 

 of agar, and brought through formol etc. into celloidin. Rather 

 thick sections (50 u) were stained with Hansen's haematoxylin 

 and differentiated with dilute acetic acid. Under the microscope 

 the following was to be seen: 



The bloodvessels even after 24 hours were in very good condition. 

 The agar always showed in the form of small granula, even- 

 tually mixed with some chromocytes. The colonies of bacteria 

 are very clear. Their localisation, size, and number differred 



