SYMPTOMS OF POISONING 257 



to be good forage for them. Horses are susceptible to the poison 

 if large quantities are fed experimentally; but in feeding on the 

 range at will it is not likely that they would eat enough to cause 

 serious results. 



Poisonous Parts of Plant. — All the parts of the larkspur plant 

 above ground are poisonous; most of the trouble is caused by the 

 leaves, but sometimes by the flowers also. The seeds contain 

 more active poison than the rest of the plant, but they hardly 

 ever cause death, as they are readily disseminated upon reaching 

 maturity and are not sought for by stock. After seed maturity, 

 also, the leafage seems to lose much of its toxicity. 



The low larkspurs are poisonous as long as their herbage lives, 

 but that generally lasts only through May and June. More- 

 over, the low species seldom grow densely enough for stock 

 to crop fatal amounts of the herbage. The roots of native 

 larkspurs are never eaten, as they are tough and woody and 

 difficult to get at. 



Amount Required to Cause Death. — Experiments with feed- 

 ing larkspur show that an animal must eat about 3 per cent 

 of its weight in order to be fatally poisoned. Thus, an animal 

 weighing 800 pounds would have to eat about 25 pounds of 

 either tall or low larkspur, although the fatal dose varies with 

 the age of the plant, and with the condition and idiosyncrasies of 

 the animal. On the average, if poisoning has proved fatal, it has 

 been found that the amount of larkspur eaten was 8 to 9 per cent 

 of the weight of the animal. It is evident, therefore, that 

 larkspur is not a virulent poison, and, if taken in small amounts, 

 is not dangerous. If other forage is plentiful, stock may graze 

 without harm on a range on which larkspur is growing. The 

 risk is greater in proportion to the scarcity of good feed. 



Symptoms of Poisoning. — Larkspur poisoning always causes 

 constipation, and recovery usually follows if this condition can 

 be relieved. Bloating occasionally occurs, and sometimes death 

 is caused by choking. Animals poisoned by larkspur fall in a 

 peculiar manner ; the fore legs give way, and the animal supports 

 itself by its head, and by spreading its hind legs. It usually 

 falls several times, the falls occurring at longer intervals if the 



