SPASM OF THE LARYNX 17 



favour absorption. In some cases, however, it is necessary to remove the 

 Huid from the chest bodily by means of an operation. A liberal diet and 

 very moderate exercise should be allowed when the urgent symptoms 

 have passed, but nothing amounting to work should be imposed for several 

 weeks at least. 



SPASM OF THE LAEYNX 



We have seen, in speaking of roaring and whistling, that the muscles 

 which regulate the size of the opening into the larynx are liable to become 

 thrown out of use as the result of paralysis. In the disease now to be 

 noticed the same narrowing of the orifice takes place, but in an entirely 

 different manner. In the one case it is the result of a paralysed state 

 of a certain set of muscles (abductors) which open the larynx, while in 

 the other it arises out of abnormal action or a spasmodic contraction of 

 another set (adductors), whose natural purpose it is to close it. 



Causes. — Spasm of the larynx may result from any sudden and 

 violent irritation, and from milder stimulation when the larynx is in an 

 irritable condition. The accidental entrance of food or other foreign 

 agent will sometimes bring it about, and especially when the sensibility 

 of the organ is heightened in the course of an attack of inflammatory 

 irritation. Some of the most severe and dangerous cases, however, arise 

 in the entire absence of any such condition, and from the manner in which 

 they come and go it is clear that they have a nervous origin ; but whether 

 the actual seat of the disorder be in the brain or in the nerves of the 

 larynx themselves cannot well be determined. 



Symptoms. — It is seldom that any premonitory indications mark the 

 oncoming of the disease. Horses who suffer from it usually enjoy good 

 general health, and are mostly in fair condition. The attack almost in- 

 variably comes on suddenly, and, with few exceptions, while trotting or 

 galloping. While moving along, the horse is noticed to come suddenly to 

 a stand-still. The head is raised and moved from side to side, the face 

 is pinched and wears an anxious expression, the nostrils are dilated, and 

 after a brief arrest in the breathing a loud shrill noise is heard witlf each 

 inspiration. In severe cases the horse breaks out in patchy sweat, the 

 gait becomes unsteady, the breathing gasping and troubled, and the body 

 is generally convulsed. 



The paroxysm may quickly pass away only to return when the animal 

 is caused to move, or it may be renewed from time to time at varying 

 intervals for several hours, when it disappears, leaving the patient but 

 little the worse for his trouble. 



