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 peptomzed bouillon 

 a red color is produced similar to that produced in cultures of the cholera 

 spirillum, and even 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 autopsy 

 the most constant appearance is hypersemia 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 to twelve hours. Gameleia 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. According 

 to Gameleia, chickens may be infected by giving them food contaminated 

 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 

 oedema 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 septicaemia. 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. 



Gameleia has shown that pigeons and guinea-pigs may be made immune 

 by inoculating them with sterilized cultures of the spirillum sterilized by 

 heat at 100 C. 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. 



Gameleia has claimed that by passing the cholera spirillum of Koch 

 through a series of pigeons, by successive inoculation, its pathogenic power 



