192 
4 o clock in the afternoon, and on these occasions it was generally 
necessary to cover the jars well with a thick towel. b ' 
Two classes of patients were used : Spanish labourers and West 
Indian negroes, the former rarely objected to being bitten, the latter 
occasionally fretted a little. Both classes of patients were rather 
obtuse mentally and occasionally would not feel the bite, or would 
not be able to tell correctly the number of them. One reason for 
this is to be found in the limits of the number of separate points of 
pain appreciable within a radius of three inches—the biting area of 
the jar. 
The Spanish patients’ hands occasionally reeked with the odour 
of cigarette smoke, and a few of the West Indians had used 
citronella to prevent sand-flies from biting, but in neither instance 
did this interfere with the feeding of mosquitos. The hungry 
females, if undisturbed, will gorge themselves with blood and not 
infrequently will expel a drop or two of bloody fluid per anum, 
This not only occurs at the first feeding but has been observed at 
subsequent feedings. 
After as many of the females as will bite have done so, the jars 
are taken to the laboratory, one of the gauze covers carefully 
removed and at the same time replaced by a card which is slipP ed 
out when the jar is placed on a Petri dish. The Petri dish contains 
a small Stender dish with a few drops of water and a split raisin or 
two. The jar is then placed on an ant-proof shelf in a dimly-^ hted 
place and under these conditions, with fresh food and water, 
nophelmes may be kept alive for two or three weeks. If ° ne ^ 
urr« m ° S T u * ” thG CVenin £ and does ^t care to transfer * 
uncover tlmrn by artificial light, the gauze may be moistened 
morning PS ^ ^ ^ ^ jars P laced on the shelf a"* 1 
At the time of biting the patient, two or three good blood 
for taming were taken and differential counts of leucocy tes as 
tie proportion of gametes to leucocvtes made the ^ l 
was pofsiblf ^ f meanS ’ and by an ° CCasionaI ^ucocyte ^ 
was possible to estimate from films the number of gametes ^ 
by the mosquito in feeding. s 
. 
