The method worked out by Mr. Le Prince and his assistants was original with them. They would take a screened cage containing a large number of anopheles mosquitoes, and spray them with a solution of analine blue; take them down at night and release them at the suspected spot. They would erect a tent at some convenient place in the town to be examined, put a mosquito-bar in this tent with a man under it as a bait for the lady anopheles, leave the bar open during the night, closing it early in the morning before the anopheles which had bitten during the night had an opportunity to escape. The mosquitoes under the bar were caught and carefully examined. If any blue-stained mosquitoes were found, it was proof that they had come from the point at which the stained mosquitoes had been released the evening before. The job of acting as bait for the mosquitoes during these investigations was a position much sought after by our negro employees. They were paid by the hour the same wages that the day-laborers received. To be paid full wages for sleeping in a comfortable bed struck the Jamaican as being as near complete bliss as was to be found in this world. Mr. Le Prince did a great deal of work in experimenting upon the flight of the anopheles at other stations, and during his investigations came across many curious things as to the habits and tastes of the anopheles. He found that the anopheles would show a marked preference for a particular horse; though there might be several other horses near and accessible, they would bite this one horse almost exclusively, the taste of whose blood they seemed to prefer. The same thing was true of men. We had one inspector of whom the mosquitoes were excessively fond. When they were not very numerous, they would scarcely trouble his companions at all, devoting all their attention to him. This poor fellow died as a result of this kind of work. He was Mr. Le Prince’s main dependence for investigations of this kind. He did not suffer particularly from malarial fever while on the Isthmus, but a short time after his return to his northern home, he died of an attack of pernicious malarial fever. These various methods of combating malaria were very successful. In some of the towns, as I have already said, they were just as successful as they had been in the city of Havana, and I myself have no doubt that, if we could have continued the methods which we inaugurated on the Isthmus, we should have been just as successful with malaria at Panama as we had previously been with the disease at Havana, and at no greater cost. As it was, we succeeded in so protecting the force against malaria that it did not interfere to any appreciable degree with its working capacity. CHAPTER XV THE WORK AT THE HOSPITALS