1865.] Dr. Davy on the Temperature, fyc., of Birds. 441 



common fowl would have to be placed amongst those birds, few in number, 

 chiefly palmipedes, ocean-birds, peculiar for lowness of temperature *. Now, 

 as neither of these conclusions is admissible, it seems unavoidable that Mr. 

 Hunter's results must be received as inaccurate. 



II. Of the expired Air, and of the Air in the Air-receptacles and Bones of 



Birds. 



1 . Of the expired air. That which I have examined has been obtained 

 from birds in the act of drowning. It is worthy of remark, I may premise, 

 and I am not aware that the fact has been noticed by any previous in- 

 quirer, that different birds vary as to their power of retention of life under 

 water. The goose expires I have found in about ten minutes ; the duck 

 in about the same time ; the common barn-door fowl in about four or four 

 and a half minutes ; the turkey in about three minutes ; the jay in about a 

 minute and a half ; the pigeon, the carrion-crow, rook, jackdaw, in about a 

 minute ; the robin, the hedge-warbler in about the same time ; the black- 

 bird in about three-quarters of a minute ; the tawny owl, the bullfinch, 

 the house-sparrow, in about half-a-minute. Those birds which are capable 

 of retaining the air longest emit little air commonly when first submerged ; 

 but later, shortly before the extinction of life, they expel it in large quan- 

 tities ; those, on the contrary, especially the smaller birds, which soonest 

 die, expel no air in the act of drowning. 



I have examined the air from the goose in one instance only ; it was a 

 portion of the last emitted. Tested by milk of lime and phosphorus, it 

 was found to consist of 7'5 carbonic acid gas, 92*5 azote. 



The air from a duck, a small portion collected after four minutes' sub- 

 mersion, was composed of 2*38 carbonic acid, 9'52 oxygen, 88' 10 azote. 

 From another duck two portions of air were tried, one after five minutes' 

 submersion, the other after between eight and ten. The first consisted of 

 7'5 carbonic acid, 7'5 oxygen, 85 azote ; the second of 15*7 carbonic acid, 

 4'1 oxygen, 80 '2 azote. 



From the common fowl the air was examined in two instances ; in both 

 it was that which was emitted near death. Of one, the composition was 6'18 

 carbonic acid, 5'08 oxygen, 82'84 azote ; of the other, 3'3 carbonic acid, 

 779 oxygen, 88-89 azote. 



From a pigeon, the air emitted (it was pretty considerable in quantity) 

 consisted of 11-1 oxygen, 89'7 azote. 



From these results, and from a few others which I have obtained, it 

 would appear that in the air expired by birds in the act of drowning there 



* The temperature of the Procellaria (equinoctialis in one instance I found 103'5 

 in recto, in another 105. Dr. Brown-Sequard has made similar observations. See Ms 

 'Journal do la Physiologic' for January 1858. M. Ch. Martins has found the tempe- 

 rature of some sea-birds even lower, that of Procellaria glacialis 102, of Larusridi- 

 bundus 104. See his very interesting memoir on the Temperature of Northern Birds in 

 the same Journal, and in the Number before quoted. 



VOL. XIV, 2 L 



