550 NERVOUS DISEASES. 



which are a,t grass with cattle and sheep, seem to be less prone 

 to take the disease, than when these ruminants are absent. 



Australian stringhalt is generally regarded as peculiar to horses, 

 although Mr. Kendall suspects that an outbreak of disease which 

 he observed among 20 store cows, was due to it. Further proof 

 is wanting to establish the identity between this and the disease 

 from which the horses died ; but tie fact of so many cattle being 

 affected in the same way at the same season of the year, and in 

 a paddock adjoining the one where the horses were, is worthy of 

 being placed on record. 



SEASON OF ATTACK.— It is usually about the autumn wheo 

 the disease makes its appearance. 



CAUSE. — No exact information is available as to the producing 

 agent of Australian stringhalt. The following are some of its 

 supposed causes: — 



1. The eating of so-called dandelion (Hypochosris radicata), 

 introduced into Australia from Great Britain, and which is known 

 as cat's ear or flatweed. The fact that it has no connection with 

 Australian stringhalt is proved by the great numbers of horses 

 eating it, and never having the disease. It is known to exist in 

 localities free from this weed, which has no medical or poisonous 

 properties. Besides, it is not a disease producer in the country 

 of its origin. 



2. The Richmond outbreak was attributed to a metallic poison 

 known as venadium, which was found, on analysis, to exist in the 

 clay taken from the water-hole supplying the affected paddock, the 

 water being very low at the time; and the fact of the disease 

 being only in this paddock, and recurring year after year in it, 

 strengthened the assumption. At Camden, where the disease was 

 very severe, and in one paddock only, the water supply was from 

 a running stream, and no venadium could be detected, so the 

 venadium theory is untenable. 



3. The fact that the disease is confined to Australia, shows that 

 it is not caused by chill, rheumatism, or any of the known kinds 

 of intestinal worms, ticks, or blood-sucking flies. 



4. A study of the respective symptoms and course of kumree 

 (p. 542), ordinary stringhalt (p. 548), and chorea (St. Vitus's dance) 

 (p. 563) proves that none of these diseases is similar to Australian 

 stringhalt. 



DURATION OF AN ATTACK.— The attack is sudden in all 

 forms of the disease. A horse may apparently be in good health 

 one day, and badly affected the next, and it not infrequently 



