KOARlJSGr. 387 



years old and very rarely attacks him, in the first instance, after 

 he is seven. 



liOARlNG FllOM MECHANICAL OBSTRUCTION IN THE AIR 

 PASSAGES. — As a result of laryngitis, bronchitis and other 

 diseases, the interior of the air passages may become rough, 

 diminished in size, or altered in structure. We may thus have 

 thickening and even ossification of the arytenoid cartilages (which 

 form the front part of the roof of the larynx), and swelling of the 

 mucous membrane, with roaring as a result. This form of roar- 

 ing may also be caused by the presence of tumours which obstruct 

 the opening of the larynx. Such tumours sometimes cause inter- 

 mittent roaring. 



ROARING FROM MECHANICAL ALTERATION OF THE 

 SHAPE OF THE AIR PASSAGES.— I have seen this form of 

 roaring caused by an attack of osteoj^orosis (p. 260) Avhich dis- 

 torted the shape of the nasal cavities. It may be due to irregular 

 or imperfect union of the edges of the wound made into the wind- 

 jDipe by an operation for tracheotomy. The continued use of a 

 very tight bearing rein is said to have occasionally caused roaring, 

 by distortion of the larynx. 



ROARING FROM POISON.— Several Continental writers have 

 described cases of roaring (probably of the paralytic form) which 

 were caused by the eating of certain poisonous plants, and which 

 were complicated as a rule by other disorders. The chief plants in 

 question are : The ordinary lentil {ervum lens), bitter lentil {ervum 

 ervilia), com cockle (cigrostemma githago), and the vetchlings 

 {lathyrus cicera and lathyrus sativus) (p. 588). Cadeac tells us that 

 in lathyrus cicera, these substances are chiefly oxalic acid and 

 saponin. Oxalic acid is a strong poison which acts on the nerve 

 centres and on the heart, and is found in sorrel and other plants. 

 Saponin contains sapotoxin, which is a dangerous blood poison and 

 breaks up the blood corpuscles (Whitla). We read in Ann Pratt's 

 '' Flowering Plants,'' that saponin occurs in soapwort (saponaria), 

 Nottingham catchfly (silene nutans), wild lynchis (lynchis diurna), 

 and chiefly in plants belonging to the order of Caryophyllese (pinks, 

 chick-weeds and carpet-weeds). The poisonous nature of many wild 

 and garden plants is due to the presence of saponin. 



TESTING A HORSE'S " WIND."— If the horse is a saddle 

 animal, he should be sent a strong gallop on soft ground, so as 

 to " open his pipes " and to allow the examiner, who, if possible, 

 ought to be in the saddle, to observe the nature of his 

 breathing. If the examination be conducted on foot, the horse, 



25^ 



