AUSTEALIAN STRINGHALT. 551 



SUSCEPTIBILITY. —Mr. Kendall tells us that it attacks all 

 classes of horses at grass, irrespective of age, sex or condition ; but 

 that it rarely affects horses which are exclusively stable-fed. 

 Animals under eighteen months old and small ponies are least 

 liable. Mr. Kendall has met with a few instances of foals and 

 yearlings which became infected. Horses which are at 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 the 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 when 

 the disease makes its appearance " (Kendall). 



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

 agent of Australian stringhalt. The following are some of its sup- 

 posed causes : — 



1. The eating of so-called dandelion [Hypochceris radicata), which 

 was introduced into Australia from Great Britain, and which is 

 known as cat's ear or flatweed. The fact that it " has no con- 

 nection 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 " {Stanley). Besides, it is not a disease pro- 

 ducer in the country of its origin. 



2. " The Richmond outbreak was attributed to a metallic poi-on 

 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, strength- 

 ened 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 vena- 

 dium theory is untenable " {Stanley). 



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. 543), ordinary stringhalt (p. 549), and chorea (St. Vitus's dance) 



