NOTES OF A BOTANIST 
fere with one's comfort. When a person can keep 
in motion, they do not settle much on him, but 
when I am obliged to be still, as in writing or 
working with the microscope, their torment is 
scarcely bearable. 
Though I wear socks and tie my trousers round 
my ankles, and often put on gloves, they still find 
out vulnerable spots, and are especially persevering 
in biting my neck, breast, and forehead. In my 
visit to Solano (Oct. 2 and 3) I was surprised to 
not meet a single mosquito, and people who have 
come from the centre of the Casiquiari tell us that 
mosquitoes are much fewer there than here. It 
is said that many years ago San Carlos was as 
much plagued as any part of the Casiquiari, but for a 
good while mosquitoes have been scarce here. This 
year it promises to revert to its original state. 
Similar alternations of healthiness and disease 
seem not infrequent in the tropics. 
The mosquitoes here are chiefly two sorts, one 
of which, the pi'um of Brazil, is a small fly of a 
darkish colour, and bites throughout the day, 
rarely beginning earlier than 7 in the morning 
and leaving off shortly after sunset. It leaves a 
small pustule filled with blood, and to persons un- 
accustomed to it considerable inflammation is caused 
by its puncture. The Indians are accustomed to 
squeeze out the blood (extravasated), and towards 
evening it is common to see women passing in 
review each other's backs and squeezing the blood 
from each puncture with a pointed stick. By this 
means it is said ulceration is prevented. I have 
myself rarely seen ulceration supervene, and this 
only where the patient had scratched the punctures. 
