MALIGNANT EDEMA. 307 



Experiments on Animals. Horses, swine, sheep, goats, 

 dogs, pigeons, ducks, hens, rabbits, mice, and guinea-pigs 

 are susceptible to malignant edema. In guinea-pigs sub- 

 acute infection pursues quite a characteristic course. The 

 animals cower, their hair stands erect, and signs of great 

 fear set in. On the slightest touch the animals cry out. 

 Death takes place within twelve hours. On autopsy 

 there is found at the site of inoculation quite con- 

 siderable bloody edema, with a small number of gas- 

 bubbles, involving the subcutaneous connective tissue and 

 the superficial muscles. In this area the bacilli with 

 spores are found in large numbers. On the other hand, 

 the blood and the internal viscera are always free from 

 bacteria if the autopsy is performed immediately after 

 death. As long as the animal continues to live, the anae- 

 robic edema-bacilli are not capable of multiplying in the 

 oxygen-containing blood. Only after death has taken 

 place do they advance, and soon the viscera and the blood 

 are filled with them. The spleen of the animal is large 

 and diffluent. The liver and the lungs are pale, and the 

 latter are of a peculiar grayish-red color. In mice the 

 bacilli gain entrance into the blood and the internal viscera 

 during life. 



In the main, malignant edema represents an intoxication. 

 As a matter of fact, precisely the same clinical picture can 

 be developed experimentally in animals if the mature 

 bouillon-culture or the serum from the edema freed of bac- 

 teria by passage through a porcelain filter is injected intra- 

 peritoneally into guinea-pigs in rather considerable amount. 



Occurrence of the Vibrio Septicus. The bacilli of 

 malignant edema, or rather their resistant permanent forms, 

 are widely distributed in nature. They are the attendants 

 of putrefactive processes, especially those that take place in 

 the absence of oxygen. They are found present in manure, 

 in dust, and in the earth of gardens and of fields. If a 

 small amount of earth be introduced into a pocket beneath 

 the skin in a guinea-pig or a rabbit, the animal will die of 

 malignant edema. The picture developed under these con- 

 ditions is, however, not a pure one. In addition to the 

 septic vibrios a large number of other microbes will be 

 found present in the edema, and as a result of this mixed 

 infection the exudate is not merely bloody and serous, but 

 putrid and fetid. 



