IDENTITY OF THE NEMATODE WORM                   347

                                                TECHNIQUE

The collection of worms from the lesion of hump sore presents certain diffi-
culties. The most convenient site for their recovery is the demarcation line
between the central core and the periphery of a quiescent lesion. A place over
this line is selected and the sore tissue scraped off with a slightly blunt scalpel.
On thus scraping away the whole cornified layer of the superficial epithelium
and a part of the rete malpighi, a thread like projection of what appears to be
one of the ends of the female worm is seen on the surface. This is then picked up
with a pair of finely pointed forceps and placed in a petri dish containing normal
saline. The scraped up material should be placed in another petri dish con-
taining normal saline, because not infrequently an entire female worm could be
found embedded in a lump of scraped up tissue. The male worms are very minute,
and for the purpose of their collection the scraped up tissue is thoroughly teased
with a fine pair of needles, and a search is made for the parasite under one-third
objective of the microscope. For the purpose of an immediate examination
the embryonated ova could be collected by teasing a gravid female on a slide
in a drop of normal saline. Plenty of ova are thus liberated either individually
or in lumps which represent parts of the uteri. The saline film on the slide is
then allowed to dry up so as to fix up the ova. The preparation is then stained
with Leishman or Giemsa stain.

Certain anatomical features such as the cuticular spines, the vulva and the
vagina could be seen best in a living specimen. Beechwood creosote has been
used as a clearing agent to see various other details, such as the nerve ganglia,
tubular oesophagus, and the spicules in the male.

               A GENERAL DESCRIPTION OF THE PARASITE

Freshly recovered parasites from the sore have frequently been found covered
with fragments of sore tissue towards their anterior extremity. The female
parasites have always been found predominating over the male ones in number,
and in collections made from several cases the numerical ratio between the male
and the female has been 1 : 3. When placed in normal saline, the worms exhibit
sluggish movements. They are small, whitish and thread like worms, the females
being two to three times larger than the males. The anterior extremity of the
male and the female which carries the mouth is slightly attenuated. The mouth
opening (Plate XXIII, Fig. 4) is minute, circular and bordered with a notched
chitenous ring. Immediately behind the mouth is a prominent conical structure
(Plate XXII, Fig. 1, and Plate XXIII, Fig. 4) from which the mouth appears to
be protruding anteriorly. At the base of the oral protrusion the thick conical
structure is encircled with a single complete ring of cuticular spines (Plate XXIII,
Fig. 4) which in some specimens also shows group arrangement at places. The
cuticle is smooth over the conical structure, and commencing with a deep notch