160 Retrospective Criticism. 



relation to any other object. It certainly does not seem cal- 

 culated to expel or disturb the vermin that may lodge there ; 

 and I remarked that it never occurred except when the bird 

 had been applying its bill to the gland, as above mentioned. 

 However, Mr. Waterton and any one who doubts this oiling 

 may readily judge for themselves. Let them take a common 

 duck, and shut it up for two or three days, so that it can 

 have no access to water, except for the purpose of drinking, 

 and, at the end of that time, let them turn it out, and allow 

 it to go to a brook or pond : it will give itself a thorough 

 ablution, — ducking, diving, and splashing with its wings, — 

 and, on coming out, will begin to dress and arrange its 

 feathers, very frequently applying its bill to the gland on its 

 rump. If this application is not for the purpose of procuring 

 a supply of oil, perhaps Mr. Waterton will have the goodness 

 to inform us what it is for, and what end this gland answers 

 in the economy of the feathered tribe, if not that which has 

 hitherto been supposed. — T. G. Clit/ieroe, Lancashire, 

 June 30. 1832. 



On Birds using Oil from Glands. (Vol. V. p. 412.) — Sir, 

 I am, as you well know, no ornithologist, although I feel an 

 interest in the discussion (when personalities are excluded) 

 and decision (when good humour is the order of the day 

 both with pros and cons) of any qucestio vcxata [contested 

 question] in any branch of natural history. Perceiving, 

 therefore, that that interesting traveller, Mr. Waterton, has 

 endeavoured, in Vol. V. p. 412., by several apparently con- 

 clusive arguments, to disprove the fact of birds using oil 

 obtained from glands for the purpose of lubricating the sur- 

 face of their plumage, I have thought it worth while to send 

 you a notice of a fact connected with the subject, which I 

 accidentally met with on looking over a torn leaf from one of 

 the volumes of the Linncean Transactions, during a spare 

 minute*, while waiting for the keys of Sir Joseph Banks's 

 cabinet of insects, collected during Captain Cook's voyages, 

 and now deposited in the Linnaean Society's house, in Soho 

 Square. It will be seen that part of the statement appears to 

 oppose Mr. Waterton's argument. 



" Nov. 21. 1820. — Dr. Leach communicated to the meet- 

 ing of the Linnaean Society an extract from a letter ad- 

 dressed to him by Robert Scarth, Esq., containing some 

 observations on the economy of the Procellaria pelagica, or 



. 

 * Dr. Franklin says, " Take care of the pence, and the pounds will take 

 care of themselves;" a truth as applicable to the employment of time as 

 to treasure or talent ; the three ts requisite to form a thorough naturalist. 



