YELLOW FEVER. 525 



important field of serum-therapy. By careful manipula- 

 tion he has succeeded in immunizing the horse and ox to 

 large doses of the bacillus, injecting into a vein so as to 

 prevent the intense local reaction, and has found that the 

 serum of these animals has the power to protect guinea- 

 pigs from lethal doses of the bacillus. He hopes that 

 the serum will also be efficacious in the treatment of yel- 

 low fever in the human being. 



Wasdin and Geddings, in the "Report of the Com- 

 mission of Medical Officers detailed by authority of the 

 President to Investigate the Cause of Yellow Fever," 

 Washington, 1899, reach the following conclusions : 



1. That the micro-organism discovered by Prof. Gui- 

 seppe Sanarelli, of the University of Bologna, Italy, and 

 named by him the " Bacillus icteroides," is the cause of 

 yellow fever. 



2. That yellow fever is naturally infectious to certain 

 animals, the degree varying with the species ; that in 

 some of the rodents local infection is very quickly fol- 

 lowed by blood infection ; and that while in dogs and 

 rabbits there is no evidence of this subsequent invasion of 

 the blood, monkeys react to the infection the same as man. 



3. That infection takes place by way of the respiratory 

 tract, the primary colonization in this tract giving rise 

 to the earlier manifestations of the disease. 



4. That in many cases of the disease, probably a 

 majority, the primary infection or colonization in the 

 lungs is followed by a secondary infection, or a secondary 

 colonization of this organism in the blood of this patient. 

 This secondary infection may be complicated by coin- 

 stantaneous passage of other organism into the blood, or 

 this complication may arise during the last hours of life. 



5. There is no evidence to support the theory advanced 

 by Prof. Sanarelli that this disease is primarily a septi- 

 cemia, inasmuch as cases do occur in which the Bacillus 

 icteroides cannot be found in the blood or organs in which 

 it might be deposited therefrom. 



6. That there exists no causal relationship between the 

 bacillus "*" of Sternberg and this highly infectious 



