BACILLUS PYOCYANEUS. 5387 
its toxic products. Its pathogenic effects on animals 
have been carefully studied. It is pathogenic for 
guinea-pigs and rabbits. Subcutaneous or intra-peri- 
toneal injections of not too small quantities of a 
recent culture—1 ¢.c. or more of a bouillon culture— 
usually cause the death of the animal in from twenty- 
four to thirty-six hours. Subcutaneous inoculations pro- 
duce an extensive inflammatory oedema and purulent 
infiltration of the tissues; a serofibrinous or purulent 
peritonitis is induced by the introduction of the bacillus 
into the peritoneal cavity. The bacilli multipy in the 
body, and may be found in the serous or purulent fluid 
in the subcutaneous tissues or abdominal cavity as well 
as in the blood and various organs. When smaller 
quantities are injected subcutaneously the animal usu- 
ally recovers, only a local inflammatory reaction being 
set up (abscess), and it is subsequently immune against 
a second inoculation with doses which would prove 
fatal to an unprotected animal. Immunity may also 
be secured by the injection of a considerable amount 
of a sterilized culture. It is interesting to note that 
Bouchard, Charrin, and Guignard have shown that in 
rabbits which have been inoculated with a culture of 
the bacillus anthracis a fatal result may be prevented 
by inoculating the same animal soon after with a pure 
culture of the bacillus pyocyaneus. Similar results 
have been obtained by Woodhead and Wood by the 
injection of sterilized cultures of this bacillus, made 
immediately after injection with the anthrax bacillus. 
Loew and Emmerich have shown that the enzymes 
produced in the pyocyaneus cultures are capable of de- 
stroying many forms of bacteria in the test-tube, and 
have slight protecting value in the body. 
