6 
Bulletin 113. 
been left on the surface exposed to the sun. *The wilted leaves of 
the wild cherry are poisonous. In the eastern section of the State 
a scrubby cherry is found growing along the small streams and 
arroyas, and some loss in cattle has been reported. Several species 
of cherry are found growing abundantly along the ravines in the 
mountains. 
3. Poison Pound in Different Parts of Plants. Another dis¬ 
couraging feature in poisonous plant investigation is that the poison 
is not always found in the same part of the plant. In the case of 
wild hellebore, aconite, showy milkweed, thorn apple, and many 
others, the entire plant is poisonous. In wild parsnips the 
roots contain most of the poison. In lupines and yellow dock 
the seeds are dangerous. In potatoes the roots may be harmless 
and the tops poisonous. In the mountain laurel and wild cherry 
it is the leaves. In milkweeds the stems are said to be poisonous. 
In the crowfoot family it is found that the flowers are especially 
dangerous. 
4. Variations According to Season, Climate, Etc. There are 
other serious difficulties to contend with in a systematic investiga¬ 
tion of this subject. The danger of certain plants varies according 
to season, climate, character of soil, etc., from year to year. A 
dry season is generally favorable for the development of poison 
in most plants. A plant may be poisonous in one country and 
harmless in another. Jimson weed is more acfive in America than 
in Europe. Some plants become less poisonous by cultivation, such 
as wild hellebore and aconite. Where the plants contain poison 
in small quantity the native stock obtain a certain amount of im¬ 
munity and will feed without harm on a range that will prove 
disastrous to other animals. The active principle may exist per¬ 
formed in the plant, which is generally the case, or it may be formed 
by the action of ferments during mastication and digestion. 
5. Some Animals More Susceptible Than Others. Plants in¬ 
jurious to one species are harmless to others. The horse, mule, 
and goat eat poison ivy with impunity. Clover and alfalfa may 
cause a true intoxication, with bloating, under certain conditions, in 
ruminants; horses pasture upon the green plant without danger. 
Individuals of the same species show a wide divergence of sus¬ 
ceptibility to poisons. As has been well said, “What is one man’s 
meat is another man’s poison.” Poison ivy produces a violent 
inflammation of the skin on most persons. Some will escape and 
are apparently immune at one time, and equally as susceptible at 
another period of life. 
Throughout the vegetable kingdom, from bacteria all the way 
up to the mighty oak, we find species of plants poisonous under 
certain conditions, but few of them poisonous under all conditions. 
