238 POISONING. 



part in rather dry situations. The habit of the plant varies in different 

 parts of Montana. In some locahties the flowers are pure white, while 

 in others they are decidedly yellow. 



In Colorado the plant which is most ordinarily known as loco weed 

 is Astragalus moUissivms, w^hile in Montana the species already named is 

 p.erhaps most important ; but there are others which have a rather wide 

 distribution and are known to produce the same effects. Among these 

 may be mentioned A. splendens, A. lagojms, and A. hesseyi. 



The losses caused from the loco disease are very heavy in nearly all the 

 Eocky Mountain States. The locoed condition is so commonly observed 

 among sheep and horses that cases are not reported, and it is practically 

 impossible to learn the exact extent of the disease. In the Judith Basin 

 one prominent stockman was nearly ruined financially by the prevalence 

 for a number of years of the loco habit among his sheep. In another 

 instance the raising of horses was abandoned over a large tract of 

 country on account of the loco weeds. 



The loco disease occurs under two forms — an acute and a chronic. 

 An acute case of loco disease was observed by Dr. Wilcox in a two-year- 

 old ewe with a lamb at its side. The ewe was observed eating large 

 quantities of white loco w^eed on May 22nd, 1900. During the afternoon 

 of the same day it became unmanageable, and the lamb was badly 

 affected. An examination of the ewe at this time showed that it was 

 completely blind and was affected with dizziness. It walked around in 

 long circles to the right, and after a short period remained standing for 

 a few moments in a sort of stupor. At the beginning of each attack 

 the head was elevated and drawn to the right ; eyelids, lips, and jaws 

 were moved rapidly. Each attack lasted from one to two minutes? 

 and the intervals between the attacks lasted about five minutes. The 

 second day the attacks became more severe and of longer duration, the 

 head being turned more decidedly to the right and the animal sometimes 

 falling upon the ground. Similar symptoms, accompanied by digestive 

 disturbances, w^ere manifested by the lamb during the second day, and it 

 died during the afternoon. On the morning of the third day it was 

 found that the ewe was pushing against the fold, and had apparently 

 been in that position during the greater portion of the night. The 

 animal then began to whirl round to the right. Later it became unable 

 to stand, and the spasmodic movements were largely confined to the legs. 

 On the morning of the fourth day it died. The pupil of the eye was at 

 no time dilated, and the expression was nearly normal. The pulse was at 

 first very irregular, but on the second day became ag^in regular and of 

 normal frequency. The only remedy which was tried was frequent 

 injections of one-quarter grain doses of morphine, but this was without 

 effect. Two other ewes ate smaller quantities of loco weed at the same 



