98 OEIGESTAL ARTICLES. 



de novis piilmonum yasis in OpKidiis viviperiiise repertls." This* 

 treatise was printed for the use of my class, but was never pnblislied; 

 so the anatomical world took little or no notice of it. In it I stated 

 that in the genns Coluber, the middle portion of the lungs neither 

 received vessels from the pulmonary arteries nor gave branches to 

 the puhnonary veins ; but that it received arteries from' the aorta and 

 Bent veins to the vena portfe, the posterior pai't of the lungs having 

 no supply of blood-vessels at all. 



Lapse of time and further investigation have brought me many 

 additional proofs of the correctness of this statement, which I can 

 now announce with certainty to occur in all snakes. Fi'om the spot, 

 where the interior surface of the lungs loses its reticulated aj^j^earance 

 (as is the case with the posterior two-fifths of the sacciform lungs) 

 every vestige of circulation is absent. The very finest injection 

 fails to penetrate this portion, which is positively deprived of blood- 

 vessels. 



I find that the longer the body of the snake, the longer is the 

 bloodless portion of its lungs. 



The interior surface of the lungs of the thick-bodied venomous 

 snakes is, throughout its entire length, covered with hexagonal cells, 

 and these are well supplied with both arteries and veins. This is 

 also the case with the snake-like Scincoids {Pseudopus anguis) ; in 

 all other snakes only the anterior two-fifths of the lung is provided 

 with cells whose arteries come from the pulmonary artery, and 

 whose veins go to the pulmonary vein ; the third fifth receives its 

 arteries from the aorta, sending its veins to the vena portse ; whilst 

 the remaining two-fifths receive no blood-vessels at all. 



When a lung like this is inflated, it will be found that this lower 

 portion expands to double, or even triple, its former size, while the 

 anterior part expands to not more than one-half its original diameter. 

 This posterior portion of the lung, which is quite incapable of respira- 

 tion, may, therefore, be regarded as a reservoir of air, which is pro- 

 bably consumed when external circumstances, such as fiight, hyber- 

 nation, &c., prevent a regular respiration. ' ''f^^ ''' 



jjirgvery snake, when frightened or surprised, is known to inflate its 

 body to a very considerable degree, and to give utterance to a pecu- 

 liar hissing sound, AA'hich I think is neither a sign of terror nor anger, 

 nor produced by expiration, as the cry of other animals, but is the 

 necessary physical resiJt of the creature taking in rapidly a large 

 sup])ly of air in case of necessity-^ this air, passing through the small 

 glottis, causing the sniffle. ' "^ 'ivm;; ofi: loi ^o.' 



I" When I referred to the middle portion of the lungs, as receiving 

 branches from the aorta and giving branches to the vena porta", these 

 vessels miist not, for a moment, be confounded with the common 

 nutrient blood-vessels of other lungs, as in mammalia, where they are 

 well known as the arteria? et vente bronchiales ; for, were these 

 vessels in the snakes only nutrient, then would not the anterior part 

 be deprived of them. ifio>l- 



