232 POPULAR SCIENCE MONTHLY. 



For the quartering of this detachment, and of such non-immune individuals 

 as should be received for experimentation, hospital tents, properly floored, were 

 provided. These Avere placed at a distance of about twenty feet from each other, 

 and were numbered 1 to 7 respectively. 



Camp Lazear was established Xov. 20, 1900, and from this date was strictly 

 quarantined, no one being permitted to leave or enter camp except the three 

 immune members of the detachment and the members of the board. Supplies 

 were drawn chiefly from Columbia Barracks, and for this purpose a conveyance 

 under the control of an immune acting hospital steward, and having an immune 

 driver, was used. 



A few Spanish immigrants recently arrived at the port of Havana were 

 received at Camp Lazear, from time to time, while these observations were being 

 carried out. A non-immune person, having once left this camp, was not per- 

 mitted to return to it under any circumstances whatever. 



The temperature and pulse of all non-immune residents were carefully 

 recorded three time a day. Under these circumstances any infected individual 

 entering the camp could be promptly detected and removed. As a matter of 

 fact, only two persons, not the subject of experimentation, developed any rise of 

 temperature; one, a Spanish immigrant, with probable commencing pulmonary 

 tuberculosis, who was discharged at the end of three days; and the other, a 

 Spanish immigrant, who developed a temperature of 102.6° F. on the afternoon 

 of his fourth day in camp. He was at once removed with his entire bedding and 

 baggage and placed in the receiving ward at Columbia Barracks. His fever, 

 which was marked by daily intermissions for three days, subsided upon the 

 administration of cathartics and enemata. His attack was considered to be due 

 to intestinal irritation. He was not permitted, however, to return to the camp. 



No non-immune resident was subjected to inoculation who had not passed 

 in this camp the full period of incubation of yellow fever, with one exception, to 

 be hereinafter mentioned. 



For the purpose of experimentation subjects were selected as follows : From 

 Tent No. 2, 2 non-immunes, and from Tent No. 5, 3 non-immunes. Later, 1 non- 

 immune in Tent No. 6 was also designated for inoculation. 



It should be borne in mind that at the time when these inoculations were 

 begun, there were only 12 non-immune residents at Camp Lazear, and that 5 of 

 these were selected for experiment, viz., 2 in Tent No. 2, and 3 in Tent No. 5. Of 

 these we succeeded in infecting 4, viz., 1 in Tent No. 2 and 3 in Tent No. 5, each 

 of whom developed an attack of yellow fever within the period of incubation of 

 this disease. The one negative result, therefore, was in Case 2 — ISIoran — inocu- 

 lated with a mosquito on the fifteenth day after the insect had bitten a case of 

 yellow fever on the third day. Since this mosquito failed to infect Case 4, three 

 days after it had bitten Moran, it follows that the result could not have been 

 otherwise than negative in the latter case. We now know, as the result of our 

 observations, that in the dase of an insect kept at room temperature during the 

 cool weather of November, fifteen or even eighteen days would, in all probability, 

 be too short a time to render it capable of producing the disease. 



As bearing upon the source of infection, we invite attention to the period of 

 time during which the subjects liad been kept under rigid quarantine, j^rior to 

 successful inoculation, which was as follows: Case 1, fifteen days; Case 3, nine 

 days; Case 4, nineteen days; Case 5, twenty-one days. We further desire to 

 emphasize the fact that this epidemic of yellow fever, which aff'ected 33.33 per 

 cent, of the non-immune residents of Camp Lazear, did not concern the 7 non- 

 immunes occupying Tents Nos. 1, 4, 6 and 7, hut was strictly limited to those 

 individuals who had been bitten by contaminated mosquitoes. 



