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nutrients of various antiseptic products which are usually disa- 
greeable in taste and sometimes actually poisonous. For pro- 
tection against animals, far more active constituents, capable of 
acting as fatal poisons, are frequently manufactured and stored. 
Many of the most highly nutritious of vegetable products, theo- 
retically considered, are altogether unrecognized as animal foods, 
merely because of the presence in them of such poisonous con- 
stituents. 
As illustrations of such substances I may cite nux vomica seeds, 
rich in fat and albuminous materials, yet not edible because of 
the poisonous strychnine associated with them; calabar bean, 
which is as nutritious as the ordinary kidney bean, yet its poison- 
ous alkaloids causing a man or other animal to drop as though 
struck by lightning very soon after partaking freely of it; the 
jalap tuber, as nutritious as the ordinary sweet potato, yet an 
emetico-cathartic poison by virtue of the irritating resin that it 
contains. 
A far more interesting class of cases are those of cultivated 
foods, which, though now free from poisonous properties, possess 
them in greater or less degree in their natural condition 
Indeed, some of the most important foods in use still exhibit 
traces of these poisonous properties, and in some foods these 
traces may, under exceptional circumstances, become serious in 
amount. 
For example, the cassava root, from which tapioca is obtained, 
one of the most important of tropical foods, contains a substance 
which yields hydrocyanic (prussic) acid, probably the most 
deadly of all poisons. In the wild state, this poison is excessive 
in amount, but the sweet variety under cultivation loses nearly 
all of it. So delicious a fruit as the watermelon shows in its 
distinct diuretic effects the presence of traces of poisonous sub- 
stances similar to those of many poisonous species of its family, 
and the properties of the cucumber suggest those of the poisonous 
luffas, momordicas, etc. The bitter variety of quinoa, a staple food 
of the Peruvians, must be carefully washed through several waters 
before being cooked. Even the highest forms of vegetable food 
known to us, peas and beans, contain a peculiarly poisonous sub- 
