292 
Panama and Colon, the keys to the health of the Isthmus apart from 
malaria. Yellow fever was stamped ,out towards the end of 1905, and 
the attention of the Department was directed to the reduction of 
malaria. The conditions prevailing were very favourable to the 
propagation of this disease. What drainage had been done had been 
directed towards getting rid of the larger bodies of water. Vegetation 
was rank, and grew close up to the dwelling-quarters. Alongside 
the camps, consisting of unscreened houses, were native settlements, 
78 per cent, of the population of which showed malaria as a result of 
blood examinations in fresh specimens, mostly taken from adult men. 
The place was swarming with Anophelines. White men direct from the 
North, as well as negroes, were placed in the camps. The negroes 
spent their evenings in the native villages. In December, 1905, of 
the total employees 9*63 per cent, were in the hospitals with malaria. 
Systematic measures were immediately started. The general 
scheme was to cut all vegetation growing on soft or soggy places; 
to confine all water in small surface ditches, and to make a copious use 
o crude oil. To this was soon added the screening of buildings and 
cutting of all vegetation for a distance of six or seven hundred feet 
rom the houses, which distance seemed to comprise the length of 
ig t of the Anophelines. Quinine also played an important 
part. At first the labouring employees would not take the drug, but 
ey ad no objection to the more palatable mixture of quinine and 
mm su sequently tried. This mixture, giving 4 grains of quinine to 
wineg ass, was made with an inviting colour, and was very 
successful. 
maintenance of the open ditch system, involving re-grading, 
1 ^ ^ f.^ scoured out in heavy rains, removal of vegetation and 
a gae. application of larvicides, the fact of the collapsing of banks and 
rViaf fi, ^ inspection, were so expensive, besides being unsatisfactory, 
mpfli ^ orities found it necessary to use some more permanent 
annual expense in upkeep. They recognised 
1 e ere was water within reach of mosquitoes there would 
e larvae, as experience had shown that with the greatest care in the 
deLl inspection, larvae would escape 
of mai'nt " reasoned that the only practical method, in view 
constdered, and a first shipment of tile was ordered and mstalled 
