Consult an English history or a cyclopædia and learn about the opium war.
FOR STUDY AND REFERENCE
Obtain samples of the following, preserving them for study and inspection in closely stoppered vials: Mocha, Java, Rio, and Sumatra coffees; green, black, and gunpowder tea. Soak a tea-leaf a few minutes in warm water; unroll the leaf and attach it to a white card, for study.
Obtain samples of gum opium, laudanum, and morphine; note the odor of the first two and the taste of the last. Remember that they are poisonous.
Unroll a cheap cigarette and note the character of the tobacco in it, using a magnifying glass.
CHAPTER XI
GUMS AND RESINS USED IN THE ARTS
Most vegetable juices exposed to the air harden into firm substances, commonly called gum. Some of these dissolve, or at least soften, in water; these technically are known as "gums," and usually are so designated in commerce. Others are insoluble in water, but dissolve readily in alcohol, in naphtha, in turpentine, or in other essential oils; these are designated as "gum-resins." Still others yield oils or pitchy substances on distillation; these are known as "oleo-resins." There are many other dried vegetable juices, however, that in commerce are not classified among the gums and resins, and of these the most important is the substance commonly known as india-rubber.