Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol 1: A-Dea
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit25759/588/
576 
CETACEA. 
and one inch in breadth. The gall-bladder 
is of an elongated form, about an inch in 
diameter at the broadest part. It does not 
receive the bile by means of a communication 
between the cystic and hepatic ducts as in most 
animals, but that fluid is conveyed directly 
into it by two distinct hepato-cystic canals in 
the same manner and situation as the ureters 
terminate in the urinary bladder. The two 
orifices are half an inch apart on the same 
transverse line, and at a distance of three inches 
from the fundus vesica they are large, readily 
admitting a full-sized probe. The common 
ducts, of which they are the terminations, are 
half an inch in length, and branch off into the 
lobes on either side. The inner membrane of 
the gall-bladder is rugous; it has a longer 
investment of peritoneum than in man. Where 
it ends it is difficult to say, as it gradually 
diminishes in size after the entry of the above 
ducts, and does not appear to be separated 
from the cystic duct by any marked contraction 
or valvular structure. The cystic duct is about 
six inches in length, and two lines in diameter; 
dilates a little before entering the duodenum, 
and as it passes between the coats of that intes¬ 
tine the canal is provided with a reticular 
valvular structure of the inner membrane, 
which may probably supply the deficiency of 
this structure in the preceding parts of the 
duct. 
Three vena cava hepatica from the three 
lobes of the liver join the vena cava inferior at 
the upper and posterior edge of the liver, which 
is not, however, perforated by it as in most 
quadrupeds. The vena porta, formed in the 
usual manner, but deriving a very small branch 
from the spleen, enters the fissure below the 
gall-bladder. 
Sir Everard Home takes no notice of the 
pancreas; Sir Stamford Raffles merely observes 
that it lay ‘ below the duodenum.’ It is 
situated below and behind the pyloric cavity 
of the stomach. Its length in a Dugong six 
feet long we found to be seven inches ; it was 
obtuse and thick at the splenic or left end, 
where its diameter was two inches, and gradu¬ 
ally growing smaller towards the duodenum, 
it terminated in one uncommonly large duct, 
which was three lines in diameter and of great 
length. On laying open this canal the orifices 
of from twenty to thirty tributary ducts were 
observable, which were two lines in diameter; 
the coats of these ducts thick, and terminating 
in flattened lobules. 
The spleen, as Sir S. Raffles observes, was 
very small, of a rounded form ; its length in 
the larger specimen four inches and a half, its 
breadth in the middle one inch and a half, from 
which it tapered to either end; its structure 
finely reticular. 
In the Piked Whale the spleen is single and 
of small proportional size; in the Porpesse 
this organ is remarkable for its subdivision into 
distinct portions, of which one is generally 
about the size of a walnut (A, fig. 263) ; the 
others, to the number of four, five, or six (i, i), 
are of much smaller size.] 
The Spouting Whales always feed upon 
living food, The Dolphins and Cachalots pur¬ 
sue or catch fish principally, and large Mollusks, 
whilst Whales prey upon the numerous little 
Molluscous and articulated animals and Vermes 
which swarm, it is said, in the northern seas, 
and in the number of which are reckoned 
crustaceans, cuttle-fishes, clios, medusas, sea- 
anemonies, &c ; but in this respect a difference 
must be made between the Balænopteræ and 
the Whales, properly so called (Balana), for 
we are assured that the first also feed upon 
fish, and are capable of swallowing much- 
larger animals than the latter. 
Organs of Circulation.—The researches 
of the anatomist on the circulating system of 
the Cetaceans have not hitherto been extended 
to many species. In its essential parts it is 
similar to that in other Mammalia. But the 
peculiar nature of Cetaceans, and the great 
modifications of their organs of movement, 
have necessarily produced in this system, not 
only modifications analogous to those of these 
organs, but vascular developments exclusively 
characteristic of these animals. 
It is not known whether the Manatee pre¬ 
sents anything particular in regard to the organs 
of circulation, but the heart of the Dugong 
(fig- 264) and of the Rytina is cloven by the 
Fig. 264. 
Heart of the Dugong. 
deep separation of the two ventricles, a cir¬ 
cumstance which adds an important link of 
affinity to those already subsisting between 
these animals. 
[In the heart of the Dugong, the ventricles, 
as Sir Stamford Raffles has correctly described 
them,* are not completely detached from one 
another. The auricles are of equal size and 
of a rounded form. In the right auricle (a), 
which receives a single superior cava, the 
coronary vein, and the inferior cava, there is 
on the auricular side of the orifice of the 
latter vein a fleshy Eustachian valve, of the 
size and form which, in such cases, is com¬ 
monly seen in the human subject. The valve 
of the foramen ovale has a reticulate surface 
at the upper margin, but is entire and im¬ 
perforate. The right ventricle (b), in the Du- 
Phil. Trans. 1820, p. 174,
        

Nutzerhinweis

Sehr geehrte Benutzer,

aufgrund der aktuellen Entwicklungen in der Webtechnologie, die im Goobi viewer verwendet wird, unterstützt die Software den von Ihnen verwendeten Browser nicht mehr.

Bitte benutzen Sie einen der folgenden Browser, um diese Seite korrekt darstellen zu können.

Vielen Dank für Ihr Verständnis.