PATHOGENIC SPIRILLA. 605 
the microscope the larger liquefied areas are seen to contain yellowish-brown 
granular masses which are in active movement, and the margins are sur- 
rounded by a border of radiating filaments. In gelatin stab cultures the 
growth resembles that of the cholera spirillum, but the development is more 
rapid. Upon agar, at 37° C., a yellowish layer resembling that formed by 
the cholera spirillum is quickly developed. Upon potato no growth occurs 
at the room temperature, but at 37° C. a yellowish-brown or chocolate-col- 
ored layer is formed, which closely resembles that produced by the cholera 
spirillum under the same circumstances. In bouillon, at 37° C., develop- 
ment is extremely rapid, and the liquid becomes clouded and opaque, having 
a grayish-white color, while a thin, wrinkled film forms upon the surface. 
When muriatic or sulphuric acid is added to a culture in peptonized bouillon 
ared color is produced similar to that produced in cultures of the cholera 
spirillum, andeven more pronounced. In milk, at 35° C., rapid development 
occurs, and the milk is coagulated at the end of a week ; the precipitated 
casein accumulates at the bottom of the tube in irregular masses and is not 
redissolved. The milk acquires a strongly acid reaction and the spirilla 
quickly perish. 
Pathogenesis.—Pathogenic for chickens, pigeons, and guinea-pigs; rab- 
bits and mice are refractory except for very large doses. Chickens suffering 
from the infectious disease caused by this spirillum remain quiet and somno- 
lent, with ruffled feathers; they have diarrhoea; the temperature is not ele- 
vated above the normal, as is the case in chicken cholera. At the autops. 
the most constant appearance is hyperzemia of the entire alimentary canal. 
A_grayish-yellow liquid, more or less mixed with blood, is found in con- 
siderable quantity in the small intestine; the spleen is not enlarged and the 
organs generally are normal in appearance. In adult chickens the spirillum 
is not found in the blood, but in young ones its presence may be verified by 
the culture method and by inoculation into pigeons, which die in from 
twelve to twenty hours after being inoculated with two to four cubic cen- 
timetres. The pathological appearances in pigeons correspond with those 
found in chickens, but usually the spirillum is found in great numbers in 
blood taken from the heart. A few drops of a pure culture inoculated sub- 
cutaneously in pigeons or injected into the muscles cause their death in 
eight td twelve hours. Gameléia claims that the virulence of cultures is 
greatly increased by successive inoculations in pigeons, but Pfeiffer has 
shown that very minute doses are fatal to pigeons and that no decided in- 
crease of virulence occurs as a result of successive inoculations. Accordin 
to Gameléia, chickens may be infected by giving them food sf hear | 
with the cultures of the spirillum, but pigeons resist infection in this way. 
Guinea-pigs usually die in from twenty to twenty-four hours after receiving 
a subcutaneous inoculation ; at the autopsy an extensive subcutaneous 
cedema is found in the vicinity of the point of inoculation, and a superficial 
necrosis may be observed ; the blood and the organs generally contain the 
‘‘vibrio” in great numbers, showing that the animals die from general in- 
fection—acute septicemia. When infection occurs in these animals by way 
of the stomach the intestine will be found highly inflamed and its liquid con- 
tents will contain numerous spirilla. 
Gameléia has shown that plepons and guinea-pigs may be made immune 
by inoculating them with sterilized cultures of the spirillum—sterilized by 
heat at 100° OC. Old cultures contain more of the toxic substance than those 
of recent date. Thus two to three cubic centimetres of a culture twenty days 
old will kill a guinea-pig when injected subcutaneously, while five cubic 
centimetres of a culture five days old usually fail to do so. According to 
Pfeiffer, old cultures have a decidedly alkaline reaction, and their toxic power 
is neutralized by the addition of sulphuric acid. 
Gameléia has claimed that by passing the cholera spirillum of Koch 
through a series ef pigeons, by successive inoculation, its pathogenic power 
