560 THE ANAEROBIC BACTERIA 
or from edematous tissue of infected animals, the former being prefer- 
able. It is also desirable to inoculate a guinea-pig with some of the 
morbid material, either subcutaneously or intraperitoneally, and kill 
the animal as soon as it shows undoubted signs of infection, and procure 
cultures from the heart's blood. Pure cultures can be obtained with 
certainty, however, only by isolating strains from single spores. 
B. chauvei grows upon the surface of agar enriched with blood 
or ascitic fluid in the complete absence of oxygen, as round or oval thin 
colonies which are very delicate and tend to become confluent with 
adjacent growths. 
Conditions of Growth.— Growth does not take place below 18° C, nor 
above 44° C. The optimum is 37° to 38° C. Unusual care must be 
taken to insure completely anaerobic conditions. 
The spores are unaffected by atmospheric oxygen and remain viable 
for considerable periods of time. Half an hour's exposure to 100° C. 
will not certainly kill them, but it is stated that three to five minutes' 
heating of spores to the boiling-point of water weakens decidedly the 
virulence of vegetative organisms developing from them. 
Products of Growth.— The organism does not produce a proteolytic 
enzyme, and cultures in gelatin show no signs of licjuef action, even 
upon prolonged cultivation. Meat medium does not blacken, but a 
faint pink color frequently develops, together with a few gas bubbles. 
Milk is soon coagulated (provided the precaution is taken to heat the 
milk to 100° C. for thirty minutes, then cool quickly before inoculation) 
and some gas is usually formed. The reaction becomes acid. The 
hexose sugars, glucose, mannose, fructose, and galactose, the bioses, 
maltose, lactose and saccharose,^ are fermented with the production 
of acid and gas. 
Toxin.— Leclainche and Vallee^ and Grassberger and Schattenfroh^ 
state that filtrates of broth cultures contain a soluble toxin which is 
very poisonous for guinea-pigs in doses of 0.01 cc. Immune sera con- 
tain specific agglutinins effective in dilutions of 1 to 300. 
Pathogenesis. —The organism is not, so far as is known, pathogenic 
for man. At the site of inoculation in animals there is a rapidly spread- 
ing edema which appears to be very painful. Usually the most promi- 
nent naturally occurring lesion is a swelling of the front or hind quarters. 
The lesion practically never extends below the knee. The edematous 
area is almost black, due apparently, in part at least, to changed 
blood pigment, and the area is surrounded by a zone of hyperemia. 
The hair over the edematous area falls out easily. There is consider- 
able degeneration of the muscular tissue in the edematous zone, and 
' Meyer (Joui-. lufec. Uis., 1917, 17, 458) has described a strain which fails to form 
gas in saccharose. Diastaso and Jungano (Les Anaerobies, Paris, 1910) also state that 
saccharose is unfermented. This latter organism, however, shows evidence of being 
very proteolytic; hence the latter description cannot be regarded as that of a pure cul- 
ture of B. chauvei. 
2 Ann. Inst. Pasteur, 1900, 14, 202. 
' Ueber das Rauschbrandgift, Leipzig und AVien., 1904. 
