376 CHEMISTRY. 



The discovery of this effect of heat, so important in the 

 manufacture of India-rubber goods, is said to have been 

 made by our countryman, Goodyear, in consequence of an 

 accidental circumstance. As he was talking earnestly with 

 a friend, in making a gesture he threw into the tire a bit of 

 the compound of sulphur and caoutchouc. On taking it out 

 of the fire he observed that its properties were essentially 

 altered, and this observation led to experiments which re- 

 sulted in the discovery alluded to, and to its wide applica- 

 tion in the India-rubber manufacture. 



531. Vegetable Alkaloids. There are certain organic 

 bases, that is, bases which are extracted from the seeds, 

 bark, roots, and other parts of plants. They are called al- 

 kaloids, because, like the alkalies, they produce a basic re- 

 action on red litmus paper. We will mention a few of the 

 most prominent of them. There is morphine, which we 

 get from opium, and quinine, which we get from the cin- 

 chona bark. Caffeine, or theme, is the alkaloid found both 

 in the leaves of the tea-plant and the berries of the coffee- 

 plant. Strychnine, which is so exceedingly poisonous, is 

 obtained from the seeds of the strychnos mix vomica. 

 Nicotine is found in tobacco. It is an oily, colorless sub- 

 stance, which is so poisonous that a fourth part of a drop 

 will kill a rabbit. Most of these bases are crystalline, and 

 the crystals of some of them are beautifully delicate. Thus 

 the crystals of caffeine are fine white prisms of a silky lus- 

 tre ; and those of piperine, the active principle alike of 

 white, black, and long pepper, are white and needle-shaped. 

 Most of the organic bases, like the inorganic, unite with 

 acids to form salts. Thus morphine and quinine unite with 

 sulphuric acid to form sulphates. 



The formula of these bodies are very complex. They all 

 contain nitrogen, however, besides C, H, and O, and belong 

 to the class of bodies called Amines, as mentioned in 425. 



