11 
fall. Consequently, there is minimal stranding of drift and floatage 
due to change of level during this part of the year. Fortunately 
rises will take place during the rest of the year, and a large quan¬ 
tity of floatage and drift was landed up on the bank during the 
spring rise. 1 
In spite of this constant level there was only a very small amount 
of floatage on this pool during the June survey. There were prac¬ 
tically no pine needles, which had been so abundant the previous 
fall, and leaf floatage was absent, except in a few creeks. The cut¬ 
ting out of the trees of the pond has to this extent been an advantage. 
A large amount of drift comes down the Coosa, and this, with such 
logs of the cut trees as were not removed, formed hammocks in some 
places. It is surprising, however, how few such collections of logs 
there were. 2 
The water was mainly clear. During the June survey algae were 
not present in sufficient quantities to be a factor in the breeding of 
mosquitoes. 
Biological conditions .—The June survey also showed one thing 
very clearly, viz: The pond furnished few, if any, breeding places of 
sanitary importance for Anopheles. In the body of the pond (in¬ 
cluding bayous of affluents), they were practically not found. In 
the backwaters of creeks they were found almost exclusively just 
below the head of backwater, and in such cases in the running water 
higher up and in the pools and marshes on the sides of running water 
they were always breeding, and breeding more freely than in the 
backwater. The evidence was all in favor of these latter being 
washed down from above. This was true of Paint, Coagi (very 
few), Beeswax, and Bullace Creeks. When the running water or the 
small marshes close to the sides of the creeks were not breeding, 
larvae in numbers to be of sanitary importance were not found in the 
creek below it. The great majority of the breeding about the pond 
at this time was in the live (running) water above pond level and in 
the marshes adjacent thereto, and that in the pond was almost con¬ 
fined to the affluents about the head of backwater. It must be noted, 
however, that even if the larvae found in the backwater of creeks are 
washed down (as eggs or larvae) from live water above the pond 
level, yet the pond should be charged with the production, or a cer¬ 
tain proportion of the production, of mosquitoes which takes place 
there, as a proportion of the larvae which lodged in this backwater 
would have been washed further down and drowned had the’ pond 
not been in existence. This must be balanced against, the production 
1 By drift is meant floating stuff of all sizes. Floatage is small, or very small, floating 
stuff. (See Reprint, U. S. Public Health Reports, No. 244, p. 8.) 
2 The writers have notes of only three or four of these collections of logs. 
