612 BACTERIOLOGY. 



its use will be absolutely negative in cases in which an 

 amount of toxin has been produced sufficient to destroy 

 life. He, therefore, insists upon the early use of the 

 serum, and thus the destruction of the organism before 

 it has elaborated the fatal proportion of its toxin. It 

 is claimed that in thirty-one cases treated with the serum 

 the mortality was only 32 per cent., whereas in South 

 America, where the treatment was applied, the mortality 

 of yellow fever often rises to 50 per cent. (Sanarelli). 



Since Sanarelli' s supposed discovery a number of 

 investigations have been made into the causal relation of 

 this organism to the disease, some of which seem to 

 cast considerable doubt upon its being the specific 

 cause of yellow fever, while others are in its favor. 

 Novy, in a recent paper (September, 1898), comes to 

 the conclusion, after an exhaustive examination into 

 this subject, that the Sanarelli bacillus belongs to the 

 typhoid group, and that it is not the cause of yellow 

 fever, which is yet to be worked out. 



Novy's chief objection to this bacillus rests upon 

 the fact that yellow fever is stopped by a frost and that 

 this bacillus is not injured by much greater cold. It is 

 perfectly possible, however, that the infection is carried 

 in some indirect way, as by insects, and that the 

 carriers of infection are affected by the cold, and so the 

 dissemination of the poison is prevented. The long 

 immunity conferred by an attack and the peculiar effect 

 of cold on the spread of the disease are nevertheless 

 difficult to explain by means of the known character- 

 istics of this bacillus. In September a report by 

 Geddings and Wasdin appeared which favored the 

 claims of Sanarelli, they finding the bacilli in almost 

 every case of yellow fever, and not in any which were 



