PHYSIOLOGY AND ANATOMY OF RED GROUSE 103 



Lead pellets are often picked up by the bird amongst other objects, and 

 swallowed because they are hard and small ; but the suggestion 



•^ ' =>» Lead 



that lead poisonine; has ever resulted either in this or in any other pellets in 



■- . gizzard. 



way from the scattering of leaden shot over a moor must not be 

 taken too seriously. 



The food then having reached the gizzard with a free admixture of slightly 

 acid mucus, is now thoroughly mixed up with the grits of quartz, and ground 

 with their assistance to a pulp, the harder woody fibres soon showing Action of 

 up as whitish bits in a brownish, greenish, or reddish mess. This ^izzar . 

 vegetable pottage has now to be separated from the quartz grits, and to be 

 passed little by little into the duodenum. 



The separation is effected at the distal sphincter muscle of the gizzard, and it 

 often appears as though the sphincter was unable to distinguish readily between 

 the feel of a quartz grit and the feel of a hard seed, or the woody 



, . feeparatioii 



' "stone" of a berry. It is by no means rare to find, when a bird has of food 



•1 T c • 1 1 • T ^''°"^ grits. 



been feeding for a time on berries or wild fruits, that the gizzard 

 loses all its rock grits, and contains nothing harder than seeds, pips, or 

 woody " stones." Concurrently with this, it is sometimes found in birds 

 which, from their condition, one would have expected to have contained tape- 

 worms in abundance, that the intestines below are entirely clear of these 

 parasites. We are thus tempted to think that the passage of a Effect of 

 number of quartz grits and hard seeds may have so stimulated the f"*fnto''^' 

 peristaltic action of the intestine, and at the same time have so '"testme. 

 damaged the tapeworms that the latter have been broken ofi" at the neck and 

 discharged en masse. The worms may grow again from the attached head or 

 scolex, but it is possible that even the scolex may in many cases be dislodged, 

 and for that reason the advisability of encouraging such Grouse foods as have 

 big seeds and hard berries has sometimes been advocated. 



Be this, however, as it may, the digestible food, including our particle of 

 heather, now sufliciently pulped in the gizzard, is separated as it leaves the 

 gizzard from most of the harder and larger grits, and enters the duodenal 

 loop of the small intestine. 



The duodenum (Pis. xxvi. (c), xxvii.. Fig. 1 (d), xxvii.a, 1-2, XLiv., 

 6f inches ( = 170 mm.) in length, begins at the exit of the gizzard 

 and is U-shaped. It consists of two parallel " limbs " of about 

 equal length. These two limbs are supported and held together by a mesentery 



