474 EXPERIMENT STATION RECORD. [Vol.43 



regular but weak, and sometimes thready. Respirations are correspondingly 

 increased, 12 to 20 per minute. A few hours prior to these initial symptoms, 

 some animals show marliod indications of abdominal pain as evidenced by 

 pawing, lying down, and sometimes rolling, but this is usually of short dura- 

 tion. In all cases there is loss of appetite, and the horse becomes dull and 

 listless and invariably coughs. 



The visible mucous membranes may at first show a decided congestion, 

 sometimes accompanied by watering of the eyes. Later there may be decided 

 icterus or paleness of the mucous membranes. In most instances there is a 

 mucous or greenish colored discharge from the nostrils. The discoloration is 

 apparently due to admixture of food, as a result of paralysis of the pharynx. 



Affected animals rapidly lose flesh, become emaciated, and their coats be- 

 come rough and starring. Decided weakness is manifested by disinclination to 

 move and unsteadiness when walking. The trouble is frequently complicated 

 by pneumonic changes, and in such instances there is always a foul odor from 

 the breath. The majority of the acute cases die after six or seven days' 

 illness. A few of the less severe cases make a partial recovery, but it usually 

 terminates in the chronic form after an illness of three weeks or more. 



About 50 per cent of all cases of orchard horse disease, according to the 

 records of one veterinarian, are of the chronic type. Such animals are usually 

 in good physical condition and when at rest appear normal, but when exercised, 

 they show symptoms of difficult breathing during inspiration, accompanied 

 by a roaring sound which is due to a paralysis of the vocal cords. In most 

 cases, the condition is so severe that it is impossible to trot or walk any great 

 distance without causing distress. The working of such an animal is prac- 

 tically impossible. " Some chronic cases are apparently a sequel to the acute 

 form of the disease, while others develop so gradually as to escape notice until 

 roaring is noted. Some cases show a slight nasal mucous discharge and a 

 chronic cough which may persist for months. This condition is especially 

 prevalent in the early stages, but may later disappear." 



The principal lesions in the acute cases consist of acute inflammation of the 

 pharynx and larynx, pneumonia, and pleurisy. The mucous membranes of the 

 nasal passages, except for icterus or paleness, are normal, while all other organs 

 seem free from inflammatory disturbances. In one chronic case, the chief 

 lesion was paralysis of the left vocal cord and marked atrophy of the muscles 

 controlling it. " The liver showed a few attached shreds of fibrin on the 

 surface ; the spleen showed a sprinkling of petechial hemorrhages ; a few small 

 subserous hemorrhages were present on the heart over the left ventricle near 

 the apex. There was evidence of inflammatory disturbance tn the respiratory 

 tract, and all visceral organs were apparently normal. This animal had never 

 shown acute symptoms and had shown the roaring symptoms only about two 

 weeks prior to the time that he was killed for autopsy." 



Medicinal treatment seems to be of little value. The prognosis in all acute 

 cases is very grave, no authentic case of complete recovery having Jjeen 

 reported. "Affected horses which do not succumb in the acute stage gradually 

 get better, and after a duration of three to six weeks the disease assumes the 

 chronic form accompanied by roaring. Veterinarians at Wenatchee, W3sh., 

 who have operated for roaring upon about 100 chronic cases, have had about 

 80 per cent of the sub.1ects become serviceably sound. About half of this 

 number make a perfect recovery." 



Practical points in hog cholera control,"^T. P. White (U. S. Dept. Agr. 

 Teaihodk I'JU), pp. Jin-204, figs. 2). — This is a popular account of the control 

 work with hog cholera. 



