112 HABITS OF BIRDS. 



all during the operation ; and when it is, the sole ob- 

 ject seems to be to trim the pencil of feathers which 

 surrounds the gland. Had we any doubts upon the 

 subject, the simple experiment of covering the gland 

 in one hen or duck so as to prevent the bird having 

 access to it, and leaving it uncovered in another, for 

 a few days or weeks, would, by the state of the 

 feathers in each, set the question at rest. Independ- 

 ently of such an experiment, common to all birds, 

 the circumstance of the feathers on the head being 

 equally trim, smooth, and glossy with those on the 

 body, though they cannot be oiled, as it is impossi- 

 ble to reach the head with the bill the only instru- 

 ment by which the oil could be applied is of itself 

 fatal to the theory. 



Should we be asked what we consider to be the 

 use of the gland, we must at once say that we do 

 not know ; but our ignorance of its real use furnish- 

 es no support to the conjectural theory which the 

 preceding facts prove to be erroneous, no less than 

 some others connected with cleanliness which we 

 shall now mention. 



The Mohammedan Arabs of the desert, when they 

 cannot procure water to perform the stated ablutions 

 enjoined by the Koran, have recourse to dry sand, 

 with which they rub their bodies as a substitute; 

 and it is no doubt as a substitute for washing that 

 some birds, thence called pulverizers (Pulvinatores), 

 are fond of squatting in dust and hustling it into their 

 feathers. A familiar instance of pulverizing may be 

 observed in the barndoor fowl, even the unfledged 

 chickens of which we have observed muddling in the 

 dust by instinct, it should seem, as they were too 

 young to have learned the practice from experience 

 or by imitation. Now, had the feathers of these 

 pulverizers been previously smeared with any unc- 

 tuous matter, such as that in the rump-gland, the 

 dust would have adhered, and thus tended to soil 

 rather than to cleanse them. 



