SMELL. 287 



the weak impressions of particles widely diffused through 

 the surrounding medium, or slightly adhering to those bo- 

 dies, with which the object of their pursuit may have come 

 into contact. 



The olfactory bones of birds are constructed very much 

 on the model of the spiral bones of herbivorous quadrupeds, 

 and vary but little in the different species. Fig. 386 exhi- 



386 



bits their appearance in the Turkey: but the size of the ol- 

 factory nerves of birds of prey greatly exceeds that of the 

 same nerves in granivorous birds. In the latter, indeed, 

 they are exceedingly small; and as the natural food of that 

 tribe has but little odour, we find that they are easily de- 

 ceived by any thing which bears a resemblance to it. Sir 

 Busick Harwood relates that some poultry, which were 

 usually fed with a mixture of barley meal and water, were 

 found to have swallowed, by mistake, nearly the whole con- 

 tents of a pot of white paint. Two of the fowls died, and 

 two others became paralytic. The crops of the latter were 

 opened, and considerably more than a pound of the poison- 

 ous composition taken from each; and the crops, either na- 

 turally, or from the sedative effects of the paint, appeared 

 to have so little sensibility that, after the wounds were 

 sewed up, both the fowls eventually recovered. 



The olfactory nerves are conspicuous in the Duck, both 

 from their size and mode of distribution. They are seen 



