THE CONQUEST OF THE MOSQUITOES 



When the first Spanish soldiers were brought 

 over to the Isthmus to guard the coast from 

 pirates and the pack trains from robbers, forts 

 were built to lodge them safely. Fort San Lorenzo 

 was built at the mouth of the Chagres River to 

 protect shipping, and though the fort was once 

 destroyed by the pirate Morgan it was rebuilt 

 again even more strongly, and a great deal of 

 the old masonry may still be seen, overgrown 

 with jungle. 



ThCvSe early Spaniards, like everyone else of 

 that time, thought that there was something 

 dangerous in night air. As we have said, one of 

 the diseases from which they suffered most on 

 the isthmus was called ''mal-aria," which means 

 "bad air." Yellow fever was a new disease to 

 Europeans, who seem to have caught it first from 

 Mexican Indians, but they soon decided that it 

 was spread by night air, too. They believed that 

 they could keep well by shutting out all the out- 

 side air at night. 



The only openings in the big squadrooms where 

 the soldiers slept at San Lorenzo were the doors 

 like that in Figure 79. When the door was shut 

 tightly at night, the room must have been very 

 hot and stuffy indeed. 



179 



