I 
XIII. THE THORACIC VISCERA (PLUCKS) OF SOME 
LARGE MAMMAL 
Material. —Thoracic viscera (lamb or pig) obtained fresh from 
the abattoir, with as little mutilation as possible. The whole 
length of trachea, and the larynx and tongue should be included, 
also, at the posterior end, a portion of the diaphragm (and the 
liver in the case of one or two specimens). 
Orientation and Identification of the Structures Present.— 
Although the liver is an abdominal rather than a thoracic organ, 
its presence in at least a single specimen will help in orienting the 
other organs, and incidentally the general form and appearance 
of the liver itself should be noted. Identify its various lobes, the 
gall bladder, and the cystic duct leading from it to the du6denum 
(the latter not present here). Cut off and preserve small portions 
(an inch or less in each dimension) of the liver in 70% alcohol or 
5% formalin for later study. In case the material is absolutely 
fresh, smaller portions may be preserved for imbedding and 
sectioning (see p. 22). 
Note that the outer surface of the lung is covered by the thin 
smooth visceral pleura, which is continuous with both the dorsal 
and the ventral mediastinal pleurae. Note that the heart, 
enclosed within the pericardium, lies (together with the large 
blood vessels which are connected with it) in the ventral medi¬ 
astinal space, and that the oesophagus and the dorsal aorta are in 
the dorsal mediastinal space. If the material is sufficiently 
complete, trace these, and also the posterior vena cava, through 
the diaphragm. Sever the trachea and the oesophagus an inch or 
two below the larynx. Dissect the oesophagus well away from the 
dorsal wall of the larynx, leaving it attached only at the anterior 
end where it joins the pharynx. Cut off and discard the distal 
half of the tongue, together with any hanging, ragged ends of 
muscles and fat, and preserve the larynx for later study in 5% 
formalin. 
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