192 MEDICINAL AND POISONOUS PLANTS 
poisonous quantity into the blood through a scratch or other 
slight wound in the skin. 
The plants which produce alkaloids or other poisons would 
seem to be protected against the ravages of herbivorous 
animals by means of these substances. All such animals, 
however, are not affected alike by them. Thus cattle eat 
poison-ivy without harm, and various insects are known to 
feed exclusively upon plants which are deadly poisons to 
higher animals. Commonly poisons are associated with rank 
odors or disagreeable tastes, but in some poisonous plants 
which are avoided by cattle and sheep there are no such 
warnings that we can discover. In the plant’s economy the 
substances in question are to be considered simply as by- 
products which are sometimes protective. It is a curious fact 
that many plants may be poisoned by their own alkaloids. 
For example, an opium poppy is killed if watered with a 
. solution of morphine. 
62. Plants poisonous to eat. The number of poisonous 
plants which are to be found growing wild or in gardens is 
much larger than is generally supposed, and the cases of 
poisoning annually reported are more numerous than is 
commonly realized. While it will not be possible for us to 
deal with all the species that are dangerous, it will be sufficient 
for our purpose to select for special consideration those which 
have proved most likely to cause injury. A knowledge of 
these kinds, and of the ways in which poisoning by them has 
occurred, is not only highly important in itself as a means of 
safety, but will lead to certain rules of general application. 
It will be convenient for us to group the different kinds ac- 
cording to the parts which are most dangerous. Neverthe- 
less it must be understood that when any part of a plant is 
poisonous every other part is to be regarded with suspicion. 
One of the most common ways in which poisoning occurs 
is from the eating of underground parts of plants which re- 
semble more or less closely species that are known to be 
edible. Thus it has often happened that young folks off for 
a ramble in the country come across some wild plant that 
suggests parsnip or some similar herb and has an attractive 
looking root which has perhaps been uncovered by recent 
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