24 



cation which undoubtedly exists between the pulmonary and bron- 

 chial vessels, takes place. 



If the statement I have made with reference to the bronchial veins 

 be true, those vessels do not return the blood supplied by the bron- 

 chial arteries, except so far as the latter vessels distribute it to the 

 bronchi themselves and the structures about the root of the lung ; 

 and the next point we have to examine is whether any communica- 

 tion exist between the bronchial arteries and the pulmonary arteries. 

 In all the best injections I have made, whether in man or the lower 

 animals, in which the injection was introduced by the pulmonary artery, 

 I have never found the vessels of the bronchial tubes injected unless the 

 pulmonary veins were well-filled, and in such specimens I have seen 

 vessels passing from the bronchial tubes, and joining a branch of a 

 pulmonary vein. I have found branches of the pulmonary artery 

 containing injection, when the latter has been introduced through the 

 bronchial artery ; but in such specimens I have found portions of the 

 pulmonary plexus injected, and I believe the injection has found its 

 way through the plexus into the pulmonary arteries. I have never 

 seen the vessels described by some anatomists as passing from the 

 pulmonary artery to the bronchial tubes. 



With regard to the communication of the bronchial vessels with 

 the pulmonary veins, it admits of ocular proof. It is unquestion- 

 ably more easy to inject the vessels of the finer bronchial tubes 

 through the pulmonary veins, than through the bronchial arteries at 

 the root of the lung ; it is also possible to inject those vessels to a 

 certain extent through the pulmonary veins, without injecting the 

 pulmonary plexus. On the other hand, the injection thrown in 

 through the bronchial arteries rapidly and readily finds its way into 

 the pulmonary veins. These facts seem to prove that the blood dis- 

 tributed by the bronchial arteries within the lung is poured into the 

 pulmonary veins, and that the whole vascular system of the bron- 

 chial tubes communicates with the same veins. 



It has been stated by Mr. Rainey, that the vessels of the bronchial 

 tubes anastomose at the extremity of the tubes with the vessels of 

 the " air-cells" (air- sacs). In this I cannot concur, for I have never 

 been able to fill these extreme vessels by injection through the pul- 

 monary artery. My belief is, that at the termination of the tubes, 



