114 THE GROUSE IN HEALTH AND IN DISEASE 



nematode to escape blameless in the company of the two above - mentioned 

 cestodes. Trichosoma is probably a harmful worm, but as it seldom occurs, 

 as compared with the frequency of Trichostrongylus in the caecum, the damage 

 done by it is comparatively trifling. 



In the duodenum then it is possible to have Hymenolepis present in large 

 numbers with or without engorgement of the villi, but when, as in No. 1525, 

 Hymenolepis occupies no less than 8 inches of intestine, extending from the 

 duodenum for several inches into the small intestine, the villi may be exces- 

 sively congested. In such a case, moreover, as in No. 1864, if the bird has 

 Strongylosis the congestion of the ruesenteric vessels seems to affect the 

 appearance of the duodenum also. Normally the duodenum and 

 * ne P ancreas are P a le creamy pink or white with no visible external 

 blood-vessels ; but this is altered under conditions producing con- 

 duode- gestion, to a deep red or bright purple or crimson colour over which 

 the engorged vessels ramify (see PI. xxvni., Fig. 2). 



As already stated, the villi of the duodenum may be occasionally found in 

 a state of excessive redness, with apparently no trace of a worm of any kind. 

 Such a case was No. 1391, but it was also a very bad case of Strongylosis in 

 a hen found dead, so the change may have been post-mortem only, or it may 

 have formed part of a more general congestion. 



Typically the duodenum when badly infested by Hymenolepis looks bulky 

 and translucent, swollen and soft and is of a pinkish yellow colour, with thin 

 walls. The upper end of the ascending limb is often deeply stained by contact 

 with the liver. The contents besides the Hymenolepis are fat globules, no 

 crystals, as a rule, but an abundance of shed, endothelial cells. The fluid con- 

 tents, always small in amount, of the duodenum are generally yellowish, and may 

 be blood-stained if Hymenolepis and Trichosoma are present in excessive numbers. 



It is not a rare thing to find that in a sick bird the control of the lower 



sphincter of the gizzard is lost at the point of death or somewhat earlier, and 



that the grits have passed out of the organ in large quantities into 



the duodenum. Normally the grits are retained in the gizzard for 



a considerable time, certainly for months, if they are of any size. Much 



depends upon the nature of the food, and as already explained the presence 



of hard, woody seeds may lead to the loss of most of the gizzard grits, in 



which case they are passed with the dejecta. 1 



1 Vide p. 97. 



