GANNET. 195 



From a repetition of these experiments npon several subjects, it be- 

 came evident that there was a communication between the lungs and 

 the cellular membrane that covers the greater part of the body, as well 

 as with the whole cavity of the body, but that, by reason of some val- 

 vular contrivance, the skin could not be artificially inflated through the 

 lungs, although air would readily pass in a contrary direction. It is 

 also clear that there is no direct communication between the sides. 



In order to examine this extraordinary structure, we made a longi- 

 tudinal incision the whole length of the body, a little on one side of 

 the keel, or what is commonly termed the breast-bone ; by this means 

 the membrane that connects the skin to the body, and cuts off the 

 communication between the sides, was easily examined; but nothing 

 was observed, indicating that a communication could be effected, even 

 at the will of the bird. On each side, nearly equidistant between 

 this pectoral membrane and the back, is situated another longitudinal 

 one, very similar to the last, but perforated; between this and the 

 pectoral are about nine irregular transverse membraneous septa, that 

 hold the skin firmly to the body, having a free communication with 

 each other. The skin is also furnished with a transparent cellular 

 membrane, the cells being regularly perforated close to the base of each 

 feather. At the upper part of the breast is a large bag, which extends 

 some way up the neck ; this is attached to the skin by the septa of 

 innumerable small cells, but no opening into this cellular bag could be 

 discovered ; the introduction, however, of a small pipe through an 

 artificial aperture, clearly demonstrated a passage to the lungs, as the 

 whole internal cavity of the body was inflated, and the air issued from 

 the trachea. Upon opening this bag, the passage of communication 

 with the internal parts appeared to be under the shoulder-blades, (cla- 

 vicles,) as a thin perforated membrane was perceived at the bottom, 

 leading to the thorax, not directly into the lungs, but near the part 

 where the trachea divaricates, and afterwards communicating with the 

 lungs. It could not, however, be discovered where the air could find a 

 passage from the great magazine into the cellular bag, and yet there is 

 every reason to conclude that at this part some valvular passage exists. 



Pursuing our researches, we observed at the bottom of each lobe of 

 the lungs, a considerable opening for the passage of air into the cavity 

 of the body. But what arrested our particular attention, was a won- 

 derful provision of nature for the protection of the vital parts, by 

 guarding the viscera with a strong integument, that preserves them in 

 a proper degree of moisture, and contributes to the due secretions for 

 lubricating those parts, so essential to the functions of their delicate 



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