82 THE DISEASES OP PHEASANTS. 



The most troublesome and fatal disease is that known as " the gapes," which is 

 caused hy the presence of entozoa in the trachea or windpipe. IFor the most careful 

 demonstration of the cause of this disease we are indebted to Dr. Spencer Cobbold, 

 who contributed the following account of its history and treatment to the Linnsean 

 Society : — 



"This parasite has been found and recorded as occurring in the trachea of 

 the following birds, namely, the turkey, domestic cock, pheasant, partridge, common 

 duck, lapwing, black stork, magpie, hooded crow, green woodpecker, starling, and 

 swift. I do not doubt that this list might be very much extended if ornithologists 

 would favour us with their experience in the matter. In view of adding something 

 to our knowledge of its structure, and more particularly in the hope of directing 

 general attention to the mode of checking its ravages, I have ventured to make it 

 the subject of a special communication. 



"M.J attention was recently directed to a small, diseased, almost featherless 

 <jhicken, which I at once recognised as suffering from the gapes. The bird 

 belonged to a brood consisting of eleven individuals, all of which were between six 

 and seven weeks old. The ten healthy birds had individually attained a considerable 

 size, an average example weighing 9^ ounces ; but the infested chicken had only 

 acquired a weight of 4 ounces, in consequence of the deteriorating influences of 

 impeded respiration. The strange habits of the chicken were also in keeping with 

 its physical peculiarities. It held itself entirely aloof from the other members of 

 the brood ; and, as if to make up for its defective assimilating powers, tried to add 

 to its substance by greedily devouring everything which came in its way, thus 

 constiming two or three times as much as any other member of the brood. 

 The only interruption to its constant eating during the day arose from the act 

 of gaping, which took place at irregular intervals, sometimes as often as once 

 every minute. The extension of the neck, and consequent elongation of the 

 trachea, seems to have the effect of separating or unfolding the knot of enclosed 

 parasites — sufficiently, at least, to allow of a certain degree of expiration and 

 inspiration. 



" Having obtained possession of the fowl, I operated upon it in the following 

 manner : A very small portion of carded wool having been dipped in chloroform and 

 placed in front of the bird's nostrils, it was soon rendered perfectly insensible. 

 The skin of the neck was then divided, and the trachea sUt up to the extent of 

 about a quarter of an inch ; and introducing one prong of a pair of common 

 dissecting forceps, I removed seven Sclerostomata. Six of these parasites were united 

 in pairs, the odd worm being a female from which the mate had in all likelihood been 

 rudely torn during the withdrawal of the forceps ; and if so, it escaped my 

 observation. After I had closed the external wound in the skin with a single 

 thread, the bird was permitted to wake out of its artificial sleep; and, notwith- 



