G A N N E T. 



613 



passes readily into them : and it clearly appears there 

 is no diaphragm that confines the air to the regions 

 or cavity of the breast, but that the whole of the ab- 

 domen is equally inflated by inspiration through the 

 lungs. Thus far have the scientific researches of that 

 anatomist contributed to our knowledge on this sub- 

 ject. No one appears to have noticed the pheno- 

 mena attendant on the construction of the gannet, or 

 to what further extent this circulation of aerial fluid is 

 carried in some particular species of birds ; a circum- 

 stance which demands our highest admiration, when 

 we contemplate the advantages of such a structure, 

 in conducing to the comforts, and perhaps to the very 

 existence, of these kinds of animals. 



" Several gannets having been subjected to artificial 

 inflation, we shall state the result, and relate the man- 

 ner in which the experiments were pursued. A pipe 

 was first introduced into the wind pipe (trachea), and 

 when air was propelled through it, the whole internal 

 cavity of the body was inflated, but no air passed 

 into the external cells between the skin and the body. 

 An incision was then made into the lower part o the 

 abdomen into the body, very near the vent, into which 

 the air was forced through a pipe ; the pipe in the 

 windpipe (trachea) having been previously stopped, 

 and a similar inflation ensued, without affecting the 

 exterior cells. The pipe was now removed from the 

 windpipe (trachea), and upon the air being propelled 

 with force through the pipe near the vent, it readily 

 found its way through the larynx, producing a noise 

 similar to the sound emitted by the living bird. A 

 small opening was then made in the skin, on the left 

 side, about midway between the wing and the thigh, 

 and a pipe introduced, having stopped first those 

 directly communicating with the internal parts. It 

 was now obvious that when air was forced through 

 this orifice, the skin on that side, as far as the middle 

 line of the body, was greatly inflated, extending into 

 the lower part of the neck, along the larger joints of 

 the wing, down the thigh, and also into the cavity of 

 the body ; but the right side was not in the least af- 

 fected. The pipe at the trachea being now removed, 

 the air produced a similar effect upon the larynx, as 

 before mentioned, but not so loud. Still suspecting 

 that there was a communication between the sides, 

 by means of some valvular apparatus, the right side 

 was subjected to the same experiment ; the result, 

 however, negatived our expectation, the effect pro- 

 duced being similar in every respect. 



" From a repetition of these experiments upon 

 several subjects, it became 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, 

 on account of some valvular contrivance, the skin 

 could not be artificially inflated through the lungs, 

 although air would readily pass in a contrary direc- 

 tion. It is also clear that there is no direct com- 

 munication between the sides. In order to examine 

 this extraordinary structure, we made a longitudinal 

 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 con- 

 nects the skin to the body, and cuts off the commu- 

 nication between the sides, was easily examined ; 

 but nothing was observed indicating that a communi- 

 cation could be effected, even at the will of the bird. 

 On each side, nearly equidistant between this pec- 

 toral membrane and the back, is situated another 



ongitudinal one, very similar to the last, but per- 

 forated ; between this and the pectoral are about 

 nine irregular transverse membranous septa, that 

 bold the skin firmly to the body, having a free com- 

 munication with each other. The skin is also fur- 

 nished 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 ap- 

 peared to be under the shoulder-blades (clavicles), as 

 a thin perforated membrane was perceived at the bot- 

 tom, 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 must 

 exist. 



" Pursuing our researches, we observed at the bot- 

 tom 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 

 wonderful 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 nature, which might otherwise be 

 too quickly carried off, by the constant circulation 

 of fresh air that nearly surrounds them ; for this in- 

 tegument is held only by ligaments to the back and 

 front, leaving all other parts free for inspired air. The 

 liver and intestines are firmly attached to the sur- 

 rounding- integument ; the heart is enveloped by a 

 similar covering, which is only partially connected to 

 the common one. In the trachea nothing very re- 

 markable occurs, except two small glands, about the 

 size of a pea, at the lower extremity. The tongue 

 is so extremely diminutive, as scarcely to be entitled 

 to that denomination. The clavicles, or what is 

 commonly called the merry-thoughts, which are 

 usually affixed to the point of the keel of the breast- 

 bone by a ligament, is in the gannet so firmly united 

 as to appear a part of it. From what has been al- 

 ready observed, it will not be unreasonable to con- 

 clude, that the gannet is endowed with such singu- 

 lar properties, for very different purposes than those 

 of long and continual immersion, of which we have 

 before stated it appears to be incapable. But such a 

 power of inflation must contribute greatly to lessen 

 the concussion in its rapid descent upon water, in 

 order to seize its prey. Besides, as the enlargement 

 of the surface, without materially adding to the spe- 

 cific gravity, must greatly contribute to its buoyancy, 

 both in air and water, it is well adapted for residing 

 in the midst of the most tempestuous sea, floating on 

 its surface in perfect security, and following those 

 shoals of fishes on which depends its whole existence. 

 Thus, when all other birds are compelled to seek 

 shelter in bays and creeks, the gannet is enabled to 



