ADDITIONAL NOTE ON WHOOPING-COUGH BACILLUS. 487 



torn that the animal shows before death is marked dyspnoea, which 

 appears very early and may be accounted for by the pleural exu- 

 date. A subcutaneous injection causes an edema. 



An emulsion of culture suspended in this way, and then killed 

 by toluol or by heating to 56 degrees for half an hour, when in- 

 jected into the peritoneal cavity of guinea-pigs, also causes death, 

 with phenomena of intoxication and particularly with pleural 

 exudation. It does not, however, give rise to petechiae and larger 

 doses are necessary than of the living organism. The serum of 

 the immunized horse, although strongly agglutinating, has only 

 slight antitoxic effect. Very large doses are necessary to neu- 

 tralize the bacterial emulsion so that it may be injected into the 

 peritoneal cavity without producing injury. It may be added 

 that we have only a single immunized horse, and therefore we 

 must be somewhat reserved in speaking of the properties of the 

 immune serum, as these properties may be due to the individual 

 animal employed. It is, however, very likely that horses immu- 

 nized against the whooping-cough bacillus are similar to those 

 that furnish antityphoid serum, the serum of which, although 

 showing certain properties, such as agglutination very markedly, 

 are not extremely antitoxic. This latter property we shall endeavor 

 to increase. The results obtained by treating children suffering 

 from whooping-cough with the serum in question, although at times 

 distinctive, have not yet been sufficiently marked. 



