THE TURKEY 85 



swallow. This is especially the habit of birds which feed 

 on grain and other similar substances, which are ground 

 and comminuted by the gizzard with the help of the 

 stones it is made thus to contain. Again, we all know 

 that when we sing we make use of our larynx, an organ 

 situated in quite the upper part of our throat, close 

 beneath the root of the tongue. We all also know how 

 beautifully many birds sing, and we are sure, without 

 being told, that they must have their organ of voice also. 

 Such an organ, indeed, they have, called the " syrinx." 

 But this organ of voice is placed at the bottom of their 

 throat instead of at the top ; it is situated, again, as 

 nearly as it conveniently can be to the centre of gravity. 



A very wonderful organ is the eye of a bird. To say 

 that a man has " the eye of a hawk," is highly to com- 

 pliment his power of vision. But few persons who use 

 that expression realise how great a eulogy it expresses. 

 A rapacious bird, such as a hawk, has to keep a close eye 

 upon prey which may be running about on the ground 

 while it is watched by the hawk from a great altitude. 

 When the hawk '' stoops," that is, pounces on its quarry, 

 it is necessary for it to keep its victim well in sight during 

 the whole of the hawk's rapid descent from so great a 

 height. How delicate and extensive must be the power 

 of adjustment which a hawk's eye possesses in order to 

 enable it to effect this ! 



The eye of a bird needs to be kept very clear and 

 bright, and birds possess a special mechanism for sweeping 

 the eye rapidly and often. If we watch a hawk we may 

 observe that its eye frequently becomes shrouded for a 

 moment by some delicate film passing over it, which is, 

 in fact, a third eyelid. We seem to have nothing like 

 it, but we really have the rudiment of such a structure 

 ourselves. At the inner angle of every human eye there 



