William Snow Miller 401 
the same mass does not enter the capillaries which go to join the radicles 
of the pulmonary vein. 
At the hilus of the lung I have occasionally seen pleuro-bronchial veins, 
which join the true bronchial veins, coming from the first, and sometimes 
from the first two, divisions of the bronchi within the lung (9e). 
Horse.—In the horse branches of the bronchial artery are distributued 
directly to the pleura and also reach the pleura indirectly; that is, after 
having first traversed the substance of the lung. The later branches, on 
reaching the pleura, anastomose with those that go directly to the 
pleura. 
Fic. 10. Section taken at right angles to the pleura of the lung of the 
horse. 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. 8. A. = bronchial artery. EL. V. = lymph vessels. P. V. = pul- 
monary vein. X 50. 
The main branches of the bronchial artery, which are directly dis- 
tributed to the pleura, are of large size, much larger than in any other 
lung I have studied; their walls are very thick and contain a large 
amount of smooth muscle. 
In the sheep and in man the pencil line with which the injected lumen 
of the arteries were outlined under the camera included at the same time 
the walls of the vessels; this is not the case in the horse. Fig. 9 shows one 
