23 
lege-bred men, reported occasional attacks of Anopheles mosquitoes. 
They remained clinically and microscopically negative for malaria. 
During the four months of the investigation a total of 49 cases of 
clinical malaria came under personal observation. The blood from 
35 of these cases was examined microscopically and definitely deter¬ 
mined as to type. Not a single instance of new infection was estab¬ 
lished, all of the persons affected having been ill during December, 
1914^January, 1915, and proved to have relapsed. In several, with 
severe paroxysms, plasmodial gametocytes were found. 
Since it seems fair to assume that hibernating Anopheles in this 
region can be excluded as winter carriers of malaria, we may turn 
to the consideration of the role assumed by man in perpetuating this 
disease. 
It seemed desirable, in making a parallel study of this nature, to 
include as many human beings as the number of mosquitoes dis¬ 
sected. This I have succeeded in doing by a collection of blood speci¬ 
mens made from persons most likely to have been exposed to the 
bites of the mosquitoes examined. This index, to be of practical 
value, had to be completed while mosquitoes were still hibernating 
and previous to the general flight. 
This was done during the months of February and March, 1915. 
It was aimed to obtain as many blood specimens as practicable from 
the persons living on plantations and clearings, where the bulk of 
mosquitoes had also been collected. The majority of the blood speci¬ 
mens were made from colored and white persons while at work 
clearing timber, burning trees, making ditches, and tilling prepara¬ 
tory to planting the cotton crop. Likewise homes, stores, and offices 
were visited, in addition to the facilities offered by the company’s 
physicians in obtaining blood smears from patients and visitors. 
A total of 1,184 blood specimens was collected from these sources 
and the character of the persons examined as well as the results are 
tabulated below: 
Table No. V. —Showing persons examined in February-March, 1915. 
Age (years). 
Number examined. 
Number infected. 
White. 
Colored. 
Total. 
White. 
Colored*. 
Total. 
M. 
F. 
M. 
F. 
M. F. 
M. 
F. 
1 to 3. 
7 
7 
6 
12 
13 
38 
8 ! 
1 
7 
16 
4 to 5. 
7 
3 
15 
9 
34 
2 [ 
1 
4 
3 
10 
6 to 9. 
9 
7 
27 
31 
74 
2 j 
1 
21 
9 
33 
10 to 14. 
8 
4 
75 
60 
147 
5 1. 
41 
23 
69 
15 to 19. 
6 
2 
86 
46 
140 
1 | 
1 
43 
22 
67 
20 to 29. 
18 
14 
-135 
107 
274 
9 [ 
4 
74 
43 
130 
30 to 39. 
27 
19 
114 
45 
205 
8 ! 
6 
42 
16 
72 
40 and over. 
13 
5 
170 
84 
272 
7 i 
2 
72 
14 
95 
Total. 
95 
I 60 
634 
395 
1,184 
42 
16 
297 
137 
492 
