260 The Philippine Journal of Science 1921 
All classes and varieties of individuals may become subjects 
of filariasis. The oldest patient in this series was 64 years 
of age; the youngest patient was 13, but patients may be in- 
fected at a still younger age. 
There is no doubt that for some reason the female sex in 
this region is not so subject to filariasis as is the male sex. 
This may be partially due to dress, the women keeping their 
legs and ankles much more covered than do the men. 
Of the two hundred sixty cases listed in Table 3, only five 
were women. 
I am unable to give the statistics of infection among women 
in the general population, as they are so superstitious that there 
has been great difficulty in obtaining specimens of their blood; 
but granting that the mosquito-infection theory is correct, there 
is no absolute reason why anybody and everybody should not 
become infected. 
There is no doubt that the field laborer is more subject to 
this disease, and to its severer forms, than the literary man and 
the shopkeeper. Probably the amount of leg that is normally 
bare contributes to this fact, and the rough, dirty work greatly 
assists such diseases as elephantiasis of the scrotum and leg. 
It has been surmised that the fisherman is especially sub- 
ject to the disease, but there is not sufficient evidence to support 
this assertion. Very often the immediate inhabitants of the 
seaboard are badly off and do not get sufficient to eat, and 
the exposure to salt-laden wind and blowing sand would assist 
the development of elephantoid changes. 
Let us now turn to the parasite itself and the diseases of 
which it is the cause. The embryonic form of Filaria 6 cm- 
crofti was first discovered in 1863 by Demarquay (13) in a case 
of chylous dropsy of the tunica vaginalis. In 1866 Wiiche- 
rer(46) found the same form in a case of chyluria. In 1870 
Lewis (19) confirmed this in a case in India. In 1872 the same 
observer discovered that the blood of man was the normal 
habitat of the parasite. In 1874 Sonsino, (42) without knowl- 
edge of Lewis’s discovery, made the same observation in Egypt. 
The parental form was first discovered by Bancroft, sr.,( 2 ) 
in Australia. 
The discovery of the mosquito as the intermediate host was 
made by Manson in 1877 ;(24) and Bancroft, jr.,(3) in 1899, 
demonstrated that the complete metamorphosis takes about six- 
teen days. 
Finally Low, ( 20 ) in 1900, showed that the filaria, after at- 
taining its proper development, makes its way into the proboscis 
