276 Retrospective Criticism. 



order that those parts which were ok of reach of the bill 

 might equally receive the benefit of lubrication, it applied 

 them to the feathers already lubricated. Still, unfortunately 

 for our controversy, the unctuous matter was of such an 

 invisible nature, that Mr. Henslow confesses he never could 

 detect what it was that his dove procured from the gland, 

 though the bird even allowed him to remove the feathers 

 while it was pinching the nipple. When I see birds in the 

 act of rubbing their head and cheeks on the back and other 

 parts, after bathing, or after a shower of rain, I consider it an 

 operation to get quit of the moisture; and, when I observe 

 them doing it on a dry plumage, I' fancy that they are either 

 dislodging vermin, or rectifying the disordered webs of the 

 feathers, or doing both. Perhaps, too, the act of rubbing 

 may impart to them a pleasing sensation, like unto that 

 which we ourselves receive on rubbing our faces with the 

 ItancV 130 tWiofcnq i>ni riJiw e ylJnio(no!) bajinsqo e noi;tojji}e 



llWy^Sm^^ l fohWgik /t^W^M^ American 

 squirrel" go down into a rattlesnake's stomach, tail foremost, 

 was favoured one day with an extraordinary sight of the con- 

 tents of the gland in question. He saw the entire plumage 

 of an eagle, three feet seven inches long, and ten feet two 

 inches of alar extent, in a complete state of lubricity I In 

 speaking of this eagle, he says [Vol. I. p. 119.], "the whole 

 plumage looked, upon close examination, as if it had received 

 a general coating of a thin, clear, dilution of gum arabic." 

 He tells us, also, that the glands of this eagle were '" £i- 

 arge, and their contents had the appearance of hog's 



tremely large, and their contents had the appearance 

 ^lard &^ become ranxnd(^<J l JN<$r, 



only let the reader take into consideration the proportional 

 size of the gland on the eagle's rump ; and, after comparing 

 it with the magnitude of the whole plumage, let him calculate 

 the immense quantity of lubricating oil which would be 

 absorbed by the feathers, before the plumage could exhibit 

 the appearance " of a general coating of a thin, clear, 

 dilution of gum arabic." After this, I think, he will agree 

 with me, that one hundred glands would not suffice to pro- 

 duce such a supply of lubricating matter. Moreover, Mr. 

 Audubon tells us, that, when he dissected his eagle, he found 

 the glands extremely large, and their contents had the ap- 

 pearance of hog's lard which had been melted and become 

 rancid. After the discharge of such an amazing quantity of 

 lubricating matter as that which, he says, appeared upon the 

 whole plumage of the bird, I state that the glands ought to 

 have been extremely empty, and their appearance, not ex- 

 tremely large, but extremely flaccid. By way of a concluding 

 summary, I beg to offer three short reasons why I reject the 



