History of the Nematode Worms. 333 
in length, and produces young of comparatively quite colossal size 
(0°3 millim.). The worms are usually found in considerable 
numbers together, both embryos and fully-developed organisms, 
so that the mucous membrane usually appears reddened and is 
often covered with small ecchymoses. The embryos, however, re- 
main only for a short time in the dwelling-place of their parents. 
They quit the stomach, part of them passing directly out with 
the excrements, whilst part migrate, in the manner of the embryos 
of Trichina, into the body of their host. The coat of the pleura, 
the diaphragm, liver, and lungs of the infected cats are sprinkled 
with a greater or less number of small cysts, each of which encloses 
one or more embryos. The wall of the capsule has the texture of 
connective tissue, and is so thick as not unfrequently to measure 
three or four times the diameter of the internal space. If several 
worms are present in the same capsule, each of them has its own 
cavity, which, however, it does not in general completely fill with 
its convolutions. These capsules are most frequent in the lungs, 
where they sometimes produce the appearance of a regular miliary 
tuberculosis, and give rise to a more or less widely diffused in- 
flammation. (On one occasion I examined a cat which had evi- 
dently died in consequence of this inflammation.) The bloody 
bronchial mucus usually contains considerable numbers of mobile 
embryos, whilst the muscles and other organs (as also the blood) 
are free from them. 
The organization of the embryos is very characteristic ; indeed 
the earliest states of the Nematoda in general are by no means 
so uniform and concordant in structure as is generally supposed. 
Their bodies measure about 0°3 millim. and are of the same thick- 
ness throughout (0015 millim. with a length of 0°32 millim.). 
The tail (reckoned from the anal orifice) is short and furnished 
with an S-shaped point, which is distinctly marked and projects 
towards the ventral surface over the end of the strong chitinous 
band running along the sides of the body (on the future so- 
called lateral line). The cesophagus constitutes nearly half of the 
entire intestinal tract, and contains a number of clear vesicles in 
its clavate posterior extremity. The commencement of the genital 
organs is small and placed on the ventral side, behind the middle 
of the intestine. 
From the analogy of the Trichine, we should now expect that 
these embryos would be developed in the capsules of their bearer 
into larval intermediate forms. But nothing of the kind takes 
place. Not only do we never observe any further development 
of them in the cats, but we speedily ascertain that sooner or later 
they are destroyed. The encapsuled worms gradually lose their 
mobility and their transparent appearance; they become granular, 
and finally decompose into an oyal or roundish mass, which en- 
