THE POULTRY BOOK. 
323 
VERTIGO. 
Symptoms . — Fowls affected with this disease may be observed to run round in a 
circle, or to flutter about with but partial control over their muscular actions. 
Causes . — The affection is one evidently caused by an undue determination of 
blood to the head, and is dependent on a full-blooded state of the system, usually 
the result of over-feeding. 
Treatment. — I have always found that holding the head under a stream of 
cold water for a short time immediately arrests the disease ; and a dose of any 
aperient, such as calomel, jalap, or castor oil, removes the tendency to the 
complaint. 
PARALYSIS. 
Symptoms . — An inability to move some of the limbs. In fowls, the legs usually 
are affected, and are totally destitute of the power of motion. Care must be 
taken not to confound this disease with leg-weakness, which will be described under 
the head of Diseases of the Limbs, and which requires a totally different mode of 
treatment. 
Causes . — Paralysis usually depends on some affection of the spinal cord, and 
is another result of over-stimulating diet. 
Treatment . — Nothing can be done by way of cure ; the cases may be regarded 
as hopeless, or nearly so. 
DISEASES OF THE DIGESTIVE OHGANS. 
CROP-BOUND. 
Symptoms . — The crop or membranous dilatation of the gullet, whose office it is 
to receive the food as it is swallowed, and to retain it until sufficiently softened by 
maceration, is sometimes so overcharged, that it is unable to expel its contents 
into the stomach. From the emptiness of the latter organ the bird feels hungry, 
and by continuing to eat adds to the mischief, until at last, by the contraction of 
the crop and the swelling of the grain, a hardened mass is formed, weighing in 
some cases nearly a pound, and, by the enormous protuberance it causes, giving 
evident indications of its presence. Sometimes the disease is occasioned by a single 
object being swallowed, whose size is too large to permit it to pass into the 
stomach. In this case it serves as a nucleus for other matters, and a mass is 
formed around it. I have now lying before me a piece of bone, one and a half 
inch long by three-quarters of an inch broad, which was embedded in a mass of 
horse-hair, oat-husk, and other vegetable fibres, the whole forming an egg-shaped 
solid, two and a half inches in the long, and one and a quarter inch in the 
short, diameter. This caused the death of the Dorking in whose crop it was 
found. 
Treatment . — The treatment of this disorder is very simple. With a sharp pen- 
knife an incision must be made through the skin and upper part of the crop ; the 
hardened mass loosened by some blunt-pointed instrument, and removed. If it has 
