169 



a first unsuccessful attempt had also been made on the 16th of July, was 

 again inoculated on the same day as P. U. 



August 18. This servant (J. S.) was stung by a mosquito which had 

 bitten, three days before, one of the patients of yellow fever from whom the 

 previous case was produced. J. S. remained at the "Quinta" until September 

 3d, at which date he had to return to the college in town. He was taken ill 

 on the 9th and went into a private hospital, where I was able, with Dr. 

 Delgado 's assistance, to follow up the case. 



1st day. Twenty-two days after the inoculation, taken ill in the 

 evening, with fever, headache, and pains in the loins. 



2d day. Midday: Temp. 103.1° P.; pulse 94; copious perspiration; 

 headache ; pains in the loins ; eyes injected ; tongue coated. Evening : Temp. 

 103.2° F. ; pulse 96; resp. 24; urine acid, not precipitated by boiling. 



3d day. Afternoon : Temp. 100.4° F. ; pulse 84 ; resp. 20 ; urine acid, 

 gives a distinct precipitate on being heated to the boiling point ; tongue 

 coated ; face less flushed ; thirst ; anorexia. 



4th day. Afternoon: Temp. 99.8° F. ; pulse 66; resp. 22; urine not 

 precipitated by heat nor by NO ; subicteric tint of conjunctivae ; thirst ; 

 anorexia. 



5th day. Midday: Temp. 99.3° F. ; pulse 64; resp. 22; urine turbid, 

 no albumen; appetite returning. 



6th day. Afternoon : Temp. 99.8° F. ; pulse 64 ; resp. 22 ; broth 

 allowed. 



7th day. Temp. 99.3° F. ; pulse 56 ; resp. 22 ; some appetite ; 

 conjunctivae subicteric. 



The fact that this person had returned to Havana six days before 

 the attack, together with the long incubation of twenty-two days, leaves a 

 doubt regarding the part that the inoculation may have had in the causa- 

 tion of the disease ; but, on the hand, the small number of yellow fever 

 cases reported at that time in Havana, and the circumstance that newcomers 

 are not often attacked so early as six days after arrival in the city, have 

 induced me to include this among my successful inoculations. 



From the evidence adduced in the preceding pages, I conclude that 

 while yellow fever is incapable of propagation by its own unaided efforts, 

 it may be artificially communicated by inoculation, and only becomes 

 epidemic when such inoculations can be verified by some external natural 

 agent, such as the mosquito. 



The history and etiology of yellow fever exclude from our consider- 

 ation, as possible agents of transmission, other bloodsucking insects, such 

 as fleas, etc., the habits and geographical distribution of which in no wise 

 agree with the course of that disease: whereas, a careful study 

 of the habits and natural history of the mosquito shows a remarkable 

 agreement with the circumstances that favor or impede the transmis- 



