162 



VETEEINAEY TOXICOLOGY 



of the large toxic dose of nitre, there is very little plausibility 

 in ascribing injury by maize to the presence of that salt. 



Millet {q.v.), or sorghum, contains a cyanogenetic gluco- 

 side, dwrin, and owes its dangerous qualities to the 

 formation therefrom of hydrocyanic acid 

 by enzyme action. 



In South Africa and the United States 

 poisoning by so-called ' sleepy grass,' or 

 dronk grass, is well recognised. It is 

 attributed to certain of the Graminece, 

 and to varieties of the horse-tail, or 

 Equisetum {Equisetacem) , which, for con- 

 venience, are included at this point. 

 The common European horse-tail, or 

 E. palustre (Fig. 7), is classed as 

 poisonous, though, unless given in forage, 

 there is not much likelihood of mishap 

 from it. In Connecticut, in 1871, 

 E. arvense, the field horse-tail, was 

 reported as poisonous to horses, but 

 such cases are rare, and it has been 

 suggested that the physical nature of 

 the food was to blame. In South Africa 

 E. ramosissimum is found in damp 

 localities of the Transvaal and Cape. 

 Amongst true grasses Stipa robusta is 

 noted as a narcotic, sleepy grass in 

 Arizona and New Mexico, and Melica 

 decumbens is similarly noted in the Cape. 

 Doubt as to the sstiology of these poison- 

 ings still exists, though Walsh quotes Matz 

 and Ludwig to the effect that European 

 Eqiiisetacece contain aconitic acid. 

 The Symptoms are of narcosis, recalling drunkenness, 

 during which horses and cattle stagger and wander aim- 

 lessly. A fatal end is apparently rare, removal from the 

 locality and careful dieting, along with the ordinary 

 measures of elimination, usually securing recovery. 



Pig. 7. — Equi- 

 setum Palustre 

 (Horse Tail). 



(From Smith's ' Vet- 

 erinary Hygiene. ' ) 



