PROGRESS BULLETIN 
ON THE 
LOCO AND LARKSPUR. 
By DAVID O’BRINE, Chemist. 
The literature of the so-called “loco” weed is quite exten¬ 
sive. In the Agricultural Report of 1874, page 159, we hnd 
the following, and as it describes the symptoms of the so- 
called “loco” poisoning, it is inserted here: “I think very few, 
if any, animals eat the loco at tirst from choice; but, as it re¬ 
sists the drought until other feed is scarce, they are at first 
starved to it, and after eating it a short time appear to prefer 
it to anything else. Cows are poisoned by it as well as horses, 
but it takes more of it to affect them. It is also said to poison 
sheep. As I have seen its action on the horse, the first'symp- 
tom of the poison, apparently, is hallucination. When led or 
ridden up to some little obstruction, such as a bar or rail lying 
in the road, he stops short, and if urged, leaps as though it 
were four feet high. Next, he is seized with fits of mania, in 
which he is quite uncontrollable, and sometimes dangerous. 
He rears,^ sometimes even falling backward, runs or gives 
several successive leaps forward, and generally falls. His 
eyes are rolled upward until only the white can be seen, which 
is strongly injected, and, as he sees nothing, is as apt to leap 
against a wall or man as in any direction. Anything which 
excites him appears to induce the fits, which, I think, are 
more apt to occur in crossing water than elsewhere, and the 
animal sometimes falls so exhausted as to drown in water not 
over two feet deep. He loses flesh from the first, and some¬ 
times presents the appearance of a walking skeleton. In the 
next and last stage, he only goes from the loco to water and 
back again ; his gait is feeble and uncertain ; his eyes are 
sunken, and have a flat, glassy look; and his coat is rough 
and lustreless. In general, the animal appears to perish from 
starvation, with constant excitement of the nervous system. 
