DESCRIPTIONS OF PATHOGENIC BACTERIA. 215 



be carefully studied in their relations to their 

 saprophytic adaptations, if we do not wish to 

 embrace ideas which have indeed the merit of 

 being convenient to physicians but are in 

 other respects wide of the truth. 



[I have thought it of interest to give a brief resume of Sanarelli's 

 recent papers upon yellow fever. 1 



The most important study of yellow fever that appeared before 

 Sanarelli's investigations were undertaken was that made in 1888-9 

 by Dr. Sternberg, whose researches led to an essentially negative 

 result. Sanarelli, in 7 out of 12 autopsies made upon the bodies of 

 victims of yellow fever found a specific bacillus (B. icteroides] which 

 he regards as hitherto undescribed. The reasons assigned for the 

 failure of himself and others to isolate this microbe in all cases of 

 yellow fever are : i. That B. icteroides multiplies in the human body 

 only to a limited extent, the complete and characteristic effects of 

 the disease being produced by only a very small quantity of toxin. 

 2. That this toxin, whether directly or indirectly, facilitates to a re- 

 markable degree secondary infections of all kinds. These secondary 

 infections with the colon bacillus, streptococcus, staphylococcus, 

 etc., may of themselves be fatal to the patient, and Sanarelli be- 

 lieves that the fatal termination of several cases observed by him is 

 to be explained in this way. 3. That these mixed infections not only 

 lead to the speedy disappearance of the specific microbe, but also 

 frequently end by transforming the organism of the patient into a. 

 culture medium for almost all kinds of intestinal bacteria. 



The bacteriological complications arising from these facts enhance 

 considerably the technical difficulties of isolating the specific bacil- 

 lus. Sanarelli did not succeed in finding the germ in the gastro-in- 

 testinal contents and is inclined to doubt if it usually occurs thereat 

 all ; he did, however, discover it in the circulating blood and in some 

 of the important organs of the body, notably in the liver. He re- 

 fers to the prevailing belief that the infectious material in yellow 

 fever is localized in the stomach and is to be sought for especially in 

 the black vomit, but prefers, for his part, to regard the gastric dis- 

 turbances as due to the selective action of the toxin, a view similar, 

 it will be remembered, to his interpretation of the intestinal lesions 

 of typhoid fever. 



1 Annales de 1'Inst. Pasteur, June, Sept., Oct., 1897. 



