12 THE AMERICAN BOTANIST 



productive, though there are instances of trees which have 

 yielded sugar every year for a century and are still vigorous 

 and fruitful. The tree which produces the maple sugar of 

 commerce is called for this reason the sugar maple. It ranks 

 among the finest of American forest trees. It frequently rises 

 70 feet without a branch and spreads its leaves to the sunlight 

 120 feet above its base. It is this tree which is tapped with a 

 24 inch augur, to a depth of two to six inches. The sap flows 

 through a spout inserted in each auger hole and drips into a tin 

 pail suspended under the wound. It is a slow process, about 

 seventy drops falling in a minute, but it continues ceaselessly 

 and in three weeks it may amount to 25 gallons. The sap is 

 evaporated in copper boilers, treated with a little lime to destroy 

 the bitter taste, and poured into pans to harden. From 25 

 gallons of sap about 4z J / 2 pounds of sugar are made. 



The century plant, {Agave Mexkana), surpasses even the 

 sugar maple in the quantity of matter extracted by artificial 

 bleeding. These plants are so big that you could not crowd 

 the smallest of them into a hogshead. They have leaves from 

 6 to 8 inches thick, which sprout up from the ground to the 

 height of 10 to 12 feet. Inside the leaves, there is a green cone 

 as big around as a peck measure. When the plant is ripe this 

 cone is cut out leaving a bowl which will hold about two gal- 

 lons. Into this queer bowl the sap runs from the leaves in 

 streams. Each plant produces from 8 to 15 quarts of juice a 

 day and this continues for six months. At first the juice is 

 quite sweet and clear as spring water, but it begins to ferment 

 in a very few hours and within a day has turned into> an intoxi- 

 cating drink known as "pulque", the Mexican national 

 beverage. 



Some of the minor losses through exudation are those of 

 volatile oils, gums, and resins. To the presence of the volatile 

 oils is due the fragrance of many flowers and fruits, notably 



