Symi)t(>iiis. 759 



Ihere is severe parenehyniatous iiiflainniatioii of the smallest ln-anches of the periph- 

 eral nerves, destruction of the processes of the axis cylinders and of the nerve 

 sheath, while the nerve tnmks and the spinal roots are uninjured. A more or less 

 extensive chromatolysis of individual motor nerve cells was the only lesion that 

 could be demonstrated in the cord. Cassirer on the other hand was unable to fintl 

 any lesions in either the central or perijiheral nervous system, and is consequently 

 inclined to classify the condition as a functional nervous disease and connect it 

 with Westphal's "pseudosclerosis," a disease of the human subject. 



No exact knowledge as to the nature of the disease is availal !e at the present 

 time owing to the variable or negative results of experimental investigations. Tak- 

 ing the general nature of the disease into consideration it appears to le most likely 

 that it is a polyneuritis. The negative results of the careful investigations of 

 Cassirer are not compatible Avith this supposition. 



Symptoms. The most striking syniptoiiis in the early stages 

 are, as a rnle, excital)ility and fright. The animals have a 

 scared look and the approach of a person or animal is snfficient 

 to so frighten them that they stand and tremble. The appear- 

 ance of a dog may canse collapse and epileptiform seiznres. If 

 a hold be taken of an animal many of the mnscles are thrown 

 into a state of spasmodic contraction. It is especially the mns- 

 cles of the neck that are so affected, the head being drawn back 

 in consequence. On warm days in summer the ears hang down 

 and tremble, there is nodding of the head, and there may be 

 dilatation of the pupils and nystagmus. The animals appear 

 dull and depressed to a certain extent. 



Gradually motor disturbances develop. Within one or two 

 months from the onset of the disease, and it is usually earlier 

 in warm than in cold weather, there is weakness of the quarters, 

 the gait becomes uncertain and at the same time peculiar trot- 

 ting-like movements are seen. The neck is extended and the 

 head dropped, the hind feet are separated widely from each 

 other, and very short, quick, tripping steps are taken, the joints 

 being flexed to a very slight degree. In exceptional cases the 

 feet are lifted very high and the animal walks like a fowl. 

 Owing to the weakness of the quarters the animal cannot move 

 quickly, much less jump over mounds or ditches. In the later 

 stages the fore limbs become weak, the animals stumble along, 

 keep falling down, rising being accomplished with great diffi- 

 culty. Pressure on the back causes it to sink. If an animal he 

 raised and set on its feet the joints are flexed or it falls on its 

 knees. Defecation and urination are normal up to the end. Ac- 

 cording to Cassirer the reflexes and sensibility to electrical 

 stimuli are normal. 



In the majority of cases paresthesia and severe pruritus 

 are present. In the early stages the animals gnaw at the root 

 of the tail, the gluteal region and croup, and later the hind and 

 fore legs, or they rub these parts of the body against the wall. 

 In some cases they sit like dogs so as to be able to reach the ir- 

 ritating parts better with their teeth. The l3are patches pro- 

 duced by the rubbing and gnawing become inflamed, the skin 

 being reddened and thickened and covered with thick crusts. 

 According to Funke a scratching or pricking of the affected por- 

 tions of skin causes pronounced reddening. 



