402 
FACTS IN FILARIASIS. 
Of these 309 individuals, taken thus promiscuously, 
twenty-six were found infested with the Filaria sanguinis 
hominis, that is, one in every twelve, and this proportion 
was uniform throughout the entire series, for in each of the 
300 we found eight, the other two being in the remaining 
nine. 
As, however, for want of time, we very rarely in this pre¬ 
liminary examination took more than a single lamina from 
each individual, it is probable that with more time at our 
disposal, and with more lamiads from each, we should have 
found the proportion somewhat higher, say one in ten; for 
if from a person known to have the filaria in his blood, six 
lamiads be taken, the parasite will rarely be found in all, 
seldom, indeed, in more than four; nor is the first lamina 
always one of the fertile four. Moreover, with our neces¬ 
sarily rather hurried examination, a filaria, even if present, 
may have escaped detection. 
Of the 309 individuals 16 were males, and 140 females. 
In the former were found 15, or 1 in 11J with filarids; 
in the latter 11, or 1 in 13. 
Seventy-nine were whites, 168 blacks, and 62 of mixed 
race. 
Of the 79 whites 3, or 1 in 26, had filarids. 
Of the 168 blacks 16, or 1 in 10J, had filarids. 
Of the 62 of mixed race 7, or 1 in 9, had filarids. 
The whites, should this observation be confirmed by others, 
enjoying a very marked immunity, as compared with the 
other two races. 
In the table below, ranged in decennial periods, is given 
a list of the ages of the persons examined, and the number 
of filarids found in each ; premising, that of the 15, many of 
the ages stated are simply approximative guesses. 
From 
55 
55 
55 
55 
55 
55 
1 to 10, 
11 to 20, 34 
21 to 30, 106 
14 examined and 1 filarid found 
3 
31 to 40, 
41 to 50, 
51 to 60, 
61 to 70, 
71 to 80, 
80 
45 
25 
4 
1 
55 
55 
10 
6 
5 
1 
none. 
none. 
55 
55 
55 
= 1 in 14. 
= 1 in 11. 
= 1 in 10|. 
= 1 in 13. 
= 1 in 9. 
= 1 in 25. 
The youngest age at which we found filarids was 10, the 
oldest 54. 
The 3 whites were all males. The first, an Italian, set. 
48, long resident in Brazil, suffered from commencing lymph 
scrotum. In the second visit he paid us we took six lamiads 
from the blood of the scrotum, and six from the finger. In 
