YELLOW FEVER. 405 



yellow fever. This fact is not only striking evidence in 

 favor of the specific nature of the Bacillus icteroides, but 

 it places the etiological and pathologic conception of yel- 

 low fever on an altogether new basis. ' ' 



The discovery of the Bacillus icteroides, and especially 

 of its toxin, entirely changes our view of the pathology 

 of the disease. Instead of being a disease of the gastro- 

 intestinal tract, as one would conclude from the symp- 

 toms, "all the symptomatic phenomena, all the functional 

 alterations, all the anatomical lesions of yellow fever, are 

 only the consequence of an eminently steatogenous, 

 emetic, and hemolytic action of the toxic substances 

 manufactured by the Bacillus icteroides." 



The mode by which the Bacillus icteroides enters the 

 body to produce the disease has not been made out. 

 The digestive and respiratory tracts are the most likely 

 routes. 



Sanarelli points out that when it happens that a mould 

 develops near the Bacillus icteroides, the products of 

 material exchange of this hyphomycete or the transfor- 

 mation effected by it, are sufficient to nourish the ba- 

 cillus and enable it to live and multiply, whereas it 

 would be otherwise condemned to a more or less early 

 death. 



There seems to be no particular mould possessed of this 

 power, as of six experimented upon all were capable of 

 it. Sanarelli is of the opinion that in the holds of ships 

 and in damp places generally the presence of moulds 

 favors the development of the Bacillus icteroides. 



About the same time that Sanarelli published his 

 researches, Havelburg announced l the discovery of an 

 entirely different bacillus. Without entering into a long 

 description of Havelburg' s bacillus, which seems to be 

 far less established in its specificity, the following are the 

 chief characteristic and differential points: 



The bacillus is found in the stomach and intestine and 

 in the "black vomit." It is almost the sole organ- 



1 Ann. de r Inst. Pasteur, 1897. 



