270 T. . LEWIS. 
writers on these and allied subjects, which, through the 
courtesy of Mr. Wood-Mason, Curator of the Indian Museum, 
I have been able to make, I can find no mention of their 
lodging themselves in the walls of the blood-vessels. 
(2) As far as the aorta is concerned, the condition referred 
to under the second heading is the one of most frequent oc- 
currence; and as in this conditon the parasite may be 
obtained in various stages of advancement, it will be better 
to describe the smaller tumours and their contents before 
referring more minutely to the mature Filaria, especially as 
this will give an opportunity of studying the growth of the 
parasite from a very early period till it reaches maturity. 
Specimens in almost every stage of development may some- 
times be found lodged in the walls of a single aorta. 
Although the tumours enveloping the young are much 
smaller than those in which the mature worms are usually 
lodged, the lesions, as far as the tissues of the walls of the 
artery are concerned, appear to be of a more serious nature, 
for frequently the walls of the vessel are very fragile at 
various places, and there is a considerable roughening of its 
inner wall. 
Towards the earlier stages of the attack of this parasite 
a cursory examination of either the inner or the outer sur- 
face of the aorta may not convey to the observer the impres- 
sion that there is anything unusual present, but on closer 
inspection slight indications of roughening or of dryness of 
the inner surface will be evident, as if indicative of com- 
mencing atheromatous changes. There may be eithera small 
depression at the part or a slight elevation, and when the 
artery is drawn between the finger and thumb, a little 
tubercle, varying in size from that of a millet-seed to that 
of a pea, may be more or less clearly evident. Frequently 
also, on careful examination, a thin serpentine line may be 
detected lying immediately beneath the inner coat of the artery. 
When one of the smaller tubercles is cut into and the 
tissues carefully dissected under a low magnifying power, 
a curled, hair-like object will generally be observed; this, 
when examined under a higher power, will be found to be 
an immature worm, but manifesting considerable evidence 
of organization and in a state of great activity. They may 
be so small as not to exceed +, of an inch in length or more 
than ;1,th transversely at the widest part. Some yield 
even smaller measurements than this. 
At this stage of development no reproductive organs can 
be discerned. The oral end terminates in two pointed 
papillee, dorsal and ventral, which can be brought closely 
