PATHOGENIC SPIRILLA. 565 



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 

 is greatly increased, and that when sterilized cultures of this virulent vari- 

 ety of the ' ' comma bacillus " are injected into pigeons they become immune 

 against the pathogenic action of the " vibrio Metschnikoff , " and the reverse. 

 Pfeiffer (1889), in an extended and carefully conducted research, was not 

 able to obtain any evidence in support of this claim. 



NOTES RELATING TO THE PATHOGENIC SPIRILLA. 



During the past three or four years quite a number of spirilla 

 have been obtained from various sources which resemble more or 

 less closely the spirillum of Asiatic cholera. It appears probable 

 that some of these are in fact varieties of Koch's " comma bacillus " 

 which have undergone various modifications as a result of the con- 

 ditions under which they have maintained their existence as sapro- 

 phytes. Others are evidently essentially different, and have no very 

 near relationship to the cholera spirillum. The principal points of 

 difference between these recently described spirilla and Spirillum 

 cholerse Asiatics are given in the following resume, for which we 

 are indebted to Dieudonne (1894). 



"Since the outbreak of cholera in 1892, various vibrios have been de- 

 scribed which resemble more or less closely the cholera vibrio. When these 

 are tested as to their morphological characters, growth in peptone solutions, 

 in gelatin and agar plates, cholera-red reaction, and pathogenic power, they 

 may be divided, at the outset, into two groups : viz., such vibrios as show 

 only a remote resemblance to the cholera vibrio, and therefore are easily dif- 

 ferentiated from it, and such as present only minor differences or none at 

 all that have been demonstrated. 



* ' To the first group belongs the spirillum isolated by Russell from sea 

 water Spirillum marinum which rapidly liquefies gelatin and does not 

 grow at the body temperature. Renon isolated from water, obtained at Bil- 

 lancourt, a vibrio which likewise quickly liquefies gelatin, but is not patho- 

 genic for guinea-pigs, either by subcutaneous or intraperitoneal inoculation. 

 Gimther, in examining the Spree water, found a vibrio which, upon gelatin 

 plates, formed circular colonies with smooth margins, very finely granular 

 and of a brown color. This vibrio did not give the indol reaction, and all 

 infection experiments gave a negative result. Gunther named this sapro- 



