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and b a group of three as actually discharged from the intestine of a dog in which they were thus knotted. I have often seen from six to a dozen round worms thus collected together, so as when discharged to form a solid mass as large as an egg. Like the last species they are propagated by ora, but sometimes these are hatched in the body of the parent, so that a large worm may be seen full of small ones. This species occasions much more inconvenience than the maw-worm, but still far less than the tapeworm.

Tape-worms in the dog are described by foreign writers as of five kinds, of which the Tænia solium and Bothriocephalus latus are common to man and the dog. The others are not readily distinguished from these two, and all are now said to be developed from the hydatid forms found in the livers of sheep, rabbits, &c. The peculiarity in the bothriocephalus consists in the shape of the head (see fig. 4), which has two lateral longitudinal grooves (bothria), while that of the true tænia is bemispherical. The following is a description according to Professor Owen :-" The Tænia solium attains the length of several feet, extending sometimes from the mouth to the anus. The breadth varies from one-fourth of a line at its anterior part to three or four lines towards the posterior part of the body, which then again diminishes. The head (fig. 3, a) is small, and generally hemispherical, broader than long, and often as if truncated anteriorly; the four mouths, or oscula, are situated on the anterior surface, and surround the central rostellum, which is very short, terminated by a minute apical papilla, and surrounded by a double circle of small recurved hooks. The segments of

the neck, or anterior part of the body, are represented by transverse rugæ, the marginal angles of which scarcely project beyond the lateral line; the succeeding segments are subquadrate, their

[graphic][subsumed][graphic][subsumed][subsumed][merged small]

length scarcely exceeding their breadth ; they then become sensibly longer, narrower anteriorly, thicker and broader at the posterior margin, which slightly overlaps the succeeding joint. The last series of segments are sometimes twice or three times


as long as they are broad. The gener-
ative orifices (6 b) are placed near the
middle of one of the margins of each
joint, and are generally alternate (fig. 5,
c d). The Tænia solium is androgyn-
ous; that is to say, it produces its ora
without the necessity for the contact of
two individuals, the male and female
organs being contained in each." Pro-
fessor Owen thus describes them : “In
each joint of this worm there is a large
branched ovarium (fig. 5, i), from which
a duct (n) is continued to the lateral
opening; the ora are crowded in the
ovary, and in those situated on the pos-
terior segments of the body they gener-
ally present a brownish colour, which
renders the form of their receptacle
sufficiently conspicuous. In segments
which have been expelled separately, we
have observed the ovary to be nearly
empty; and it is in these that the male
duct and gland are most easily perceived.
For this purpose, it is only necessary
to place the segment between two slips
of glass, and view it by means of a
simple lens, magnifying from 20 to 30

[graphic][merged small]

diameters. A well-defined line (9), more slender and opaque than the oviduct, may then be traced, extending from the termination of the oviduct, at the lateral opening, to the middle of the joint, and inclined in a curved or slightly wavy line to near the middle of the posterior margin of the segment, where it terminates in a small oval vesicle. This, as seen by transmitted light, is subtransparent in the centre, and opaque at the circumference, indicating its hollow or vesicular structure. The duct, or vas deferens, contains a grumous secretion; it is slightly dilated just before its termination. In this species, therefore, the ova are impregnated on their passage outward.” (Cyclopedia of Anatomy, art. Entozoa.) From this minute description it may be gathered, that the ova are in enormous numbers, each section of the worm being capable of producing them to an almost indefinite extent; and as they are passed out of the body with the fæces, it is not surprising that they are readily communicated from one dog to another, as is almost proved to be the case from the fact of their prevalence in certain kennels and absence from others. The injury caused by these worms is twofold, depending partly upon the abstraction of nourishment, which is absorbed by the worm, and partly by the irritation produced by its presence in the intestines; and hence it is of the utmost importance to get rid of so troublesome

a customer.

The Kidney-worm (Strongylus gigas) “inhabits the kidney of the dog, as well as that of the wolf, otter, raccoon, glutton, horse, and bull (see fig. 6). It is generally of a dark blood

FF 2


colour, which seems to be owing to the
nature of its food, which is derived
from the vessels of the kidney, as,
when suppuration has taken place
round it, the worm has been found
of a whitish hue.” In the human
kidney it has been known to attain
the length of three feet, with a dia-
meter of half an inch. “The head
(a) is obtuse, the mouth orbicular and
surrounded by six hemispherical papillæ
(A); the body is slightly impressed with
circular striæ, and with two longitu-
dinal impressions; the tail is incurved
in the male, and terminated by a
dilated point or bursa (B), from the
base of which the single intromittent
spiculum (6) projects. In the female
the caudal extremity is less attenuated
and straighter, with the anus (c) a
little below the apex." (Cyclopedia of
Anatomy, art. Entozoa.) I have been
thus particular in inserting descriptions
of these worms, because I find that
the study of their natural history is
becoming more general; and as there
is a large field for the microscopic

Fig. 6.

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