82 THE DISHASES OF PHEASANTS. 
The most troublesome and fatal disease is that known as ‘‘ the gapes,” which is 
caused by the presence of entozoa in the trachea or windpipe. For 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 Linnean 
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. 
“My attention was recently directed to a small, diseased, almost featherless 
chicken, 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 94 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 
consuming 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 slit 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- 
