156 Veterinary Medicine. 



Slight colds or sore throats may cause roaring so long as they 

 persist. Tight reining with the nose drawn in toward the chest 

 induces a stridor in certain animals by distorting the larynx and 

 trachea. Some horses with thick necks, badly set on heads, and 

 in a state of obesity, roar, yet the symptom subsides when the 

 superfluous fat is got rid of and they are brought into hard work- 

 ing condition. Stallions are very liable to make a noise from this 

 cause. In a case of roaring which disappeared when the horse 

 had been exercised for some time I,eblanc diagnosed an cedema of 

 the glottis which was absorbed under the increased movement of 

 the parts. He did not test his opinion by dissection. 



Roaring sometimes hereditary. That roaring runs in fam- 

 ilies there can be no doubt, but the direct cause appears to be 

 mostly the transmission of a faulty conformation. A head with 

 faulty shape and badly set on ; a thick, short neck, deficient in 

 mobility, or a small, narrow chest, predisposed to acute diseases, 

 descends from parents to offspring, entailing a predisposition to 

 roaring. The large Normandy horse is notoriously subject to 

 roaring, but then he is equally characterized by a big, coarse 

 head, narrow forehead and nostrils, big jowl, and narrow inter- 

 maxillary space. In all breeds this form is very subject to roar- 

 ing, because of the stiffness of the neck and tendency to com- 

 pression of the larynx. With the head badly set on, as it is 

 almost of necessity in these animals, everything is done to 

 produce roaring. Not only is the head cruelly reined in at work, 

 but the horse is kept a great part of his time in the stable in the 

 same or even in a worse condition, the larynx meanwhile un- 

 naturally compressed between his narrow jaws and the nerve 

 compressed or the larynx distorted. 



It must be added, however, that like some other acquired dis- 

 tortions or alterations roaring may repeat itself in the progeny. 

 Goodwin mentions an instance of it on the female side through 

 three successive generations of thoroughbreds. Of transmission 

 on the side of the male the following instance is noteworthy : 

 M. lyiphaert, an extensive proprietor in lyivonia, bought a first- 

 class English thoroughbred stallion. His progeny were healthy 

 until he became a roarer at ten years old. All his foals, got after 

 this date, followed the sire in becoming roarers, and, it is impor- 

 tant to observe, almost all at the age of ten years. 



