512 On the supposed Poiich 



Descartes, Boerhaave, and Haller, to a mechanical process; 

 Keill and Prout to chemical action ; Home, Brodie, and 

 Philip, to nervous influence. Dutrochet ascribes secretion to 

 endosmose. Perhaps none of these hypotheses are free from 

 objections ; but that which is correct with regard to animal 

 secretion, will be correct with regard to the secretions of 

 vegetables. 



{To be continued.') 



Art. hi. On the supposed Pouch under the Bill of the Rook, By 

 Charles Waterton, Esq. 



" Nee aliud quicquam . . . quaeritur, 

 Quam eorrigatur error ut mortalium, 

 Acuatque sese diligens industria." Phcedrus. 



" Nothing further is sought than to correct the errors of 

 men, and to sharpen their penetration." 



We read in that faulty work, Rennie's Montagues Ornitho- 

 logical Dictionary [p. 432.], that " the rook is furnished with 

 a small pouch at the root of the tongue." If the carrion crow 

 were as useful to man, as the rook is known to be ; if the jay 

 and the magpie had less to answer for, on the score of petty 

 plunder ; and if the jackdaw did not expose itself to persecu- 

 tion, by its prying and suspicious habits, they would all be 

 allowed by man to range at large without molestation ; and 

 then the naturalist would have that opportunity of examining 

 their economy, which at present is denied him. 



Amongst many peculiarities in these birds, scarcely known, 

 or even noticed, he would observe that at a certain time of 

 the year, and only then, they all have, at intervals, an appear- 

 ance of a pouch under the bill, quite as well defined as that 

 which is seen in the rook. The idea would then occur to 

 him, that ornithologists have either said too much, in stating 

 that the rook is furnished with a small pouch at the root of 

 the tongue ; or too little, in not telling us that the carrion 

 crow, the jay, the magpie, and the jackdaw are supplied with 

 a similar convenience. 



The real matter of fact is this, that naturalists err when 

 they ascribe a pouch to the rook. Though at times there is 

 an actual appearance of a pouch under the bill of the rook, 

 and also under the bills of the other birds just enumerated, 

 still, upon a close inspection, it will be seen that there is no 

 pouch at all in any of them. The young of all birds, from the 

 size of the thrush to that of the wren, are satisfied with a 

 single worm at one feeding, or with two, at the most. Thus, 

 in fields and gardens, we gee an old bird catch an insect, and 



