PHAGOCYTOSIS. 57 



teria ID cases in which extravasation of blood into the parenchyma 

 of the kidneys had taken place. During the first few hours after 

 intravenous injection, and before any organic changes had taken 

 place in the kidneys, the urine contained no bacteria. It was also 

 shown that no elimination took place through the intestinal canal, 

 except in cases in which the mucous membrane was the seat of 

 hemorrhagic extravasations, or other serious local lesions. In two 

 animals infected during lactation, the milk was sterile, showing 

 that no elimination took place through the mammary gland. 

 Microscopical examination revealed an increase of white blood- 

 corpuscles. Inclusion and death of bacteria in blood-corpuscles 

 were not observed. The bacteria injected into the circulation soon 

 became deposited in certain organs, notably the spleen, liver, and 

 medullary tissue of bone, and consequently separated from the cir- 

 culating blood. Non-pathogenic microbes disappear entirely and 

 permanently from the blood soon after injection. The spores 

 retain their vitality in the organism for an unusually long time ; 

 for instance, active spores of ordinary mould for 7 days, and the 

 spores of the bacillus subtilis for 62 to 78 days. 



Ribbert (Der Untergang pathogener Schimmelpilze im Korper, 

 Bonn, 1887) has also made extensive investigations concerning 

 the fate of pathogenic microbes in the organism when introduced 

 by intravenous injection. In rabbits he injected into the circulation 

 such small doses of a pure culture of aspergillus flavescens that the 

 animals did not die in consequence of the infection. On examining 

 the different organs at variable intervals after the injection it was 

 easy to determine in what manner the germs were destroyed or 

 eliminated. In the experiments made for the special purpose of 

 ascertaining the fate of microbes in the liver, the injection was 

 made directly into one of the mesenteric veins. In all other cases 

 the injection was made into one of the veins of the external ear. 

 In the liver, it was seen that when the microbes reached the capil- 

 lary vessels and the terminal branches of the portal vein they were 

 surrounded by a dense cluster of leucocytes. As long as they 

 remained within these surroundings, their multiplication appeared 

 to be retarded. Mitosis was not observed in the liver cells which 

 were compressed by the inflammatory exudation, but occasionally 

 it occurred in some of the epithelial cells lining adjacent bile-ducts. 

 The microbes were seen either disappearing directly in the sur- 

 rounding leucocytes, or some of the liver cells were transformed 

 into giant cells, into the protoplasm of which they found their 

 way, and they were destroyed. The giant cells either undergo 

 fatty degeneration and disappear with their contents by absorp- 

 tion, or they are again transformed into normal parenchyma cells. 

 When larger quantities of the same microbe were injected no such 



