William Snow Miller 403 
of the main branches near the margo inferior of the right lung and, con- 
sequently, near its final breaking up into smaller vessels. This branch 
can be readily compared with the branches of the bronchial artery in 
the pleura of the sheep and man (Figs. 7 and 11), because they are 
drawn on the same scale. In the lower part of Fig. 9 the contour lines 
indicate the thickness of the arterial walls; in the remainder of the 
drawing only the injected lumen of the artery is indicated. 
The lymphatics in the pleura of the horse, like those of the sheep, are 
supplied by the bronchial artery. In Fig. 9 the encircling network of 
blood-vessels is not as pronounced as in the sheep or in man. The 
illustration was selected more especially to show the large size of the 
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MOI, 
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Fie. 12. Section taken at right angles to the pleura of the human lung. 
Semi-diagrammatic. The outline of the section, the size and position of the 
vessels were drawn by means of the camera lucida. P.—pleura. S.—septum. 
L. V. = lymph vessels. P. V. = pulmonary vein. The branches of the bron- 
chial artery are represented by heavy black lines. X 50. 
blood-vessels. In Fig. 10 the relation between the lymph and _ blood- 
vessels is well demonstrated and one can see that there is in the horse the 
same relationship between the two systems as in the sheep and in man. 
In the pleura of the horse there is a thick, dense layer of elastic fibers 
overlaying the blood- and lymph-vessels which makes it difficult to obtain 
clear surface views of the finer blood-vessels and transparent lymph 
vessels. 
Man.—In no instance have I been able to demonstrate in the human 
pleura the long, nearly parallel, branches of the bronchial artery which 
are such a prominent feature in the pleura of the sheep and the horse: 
