43 
of bark or wood, or again, to freeze the syrup repeatedly in shal- 
low basins and throw off the ice. 
Box Elder (Acer Negundo L.), one of our most widely distrib- 
uted trees, also yields an abundant saccharine sap in the spring 
utilized by our northern and western Indians. Equally valuable, 
in this respect, is our White Walnut (Juglans cinerea L.), for “if 
tapped immediately before the leaves unfold, it yields a richly 
saccharine juice from which sugar may be obtained nearly, if not 
quite, equal to that from the Sugar Maple” (U. S. Disp.). 
Most species of Birch (Betula) yield the same quality of sap, 
and the Indians undoubtedly knew its value, although they seem _ 
to have been ignorant of the very pleasing effects of modern 
“birch beer”’ obtained by fermenting the sap of B. denta and B. 
lutea. ; 
In our western deserts, where water is scant, nature provides 
Pulpy juicy plants from which Indians can often quench their 
thirst. Chief among these are several species of cactus, especially 
of Opuntia whose fruit (prickly pear), as well as the fleshy leaves 
Or joints, contain an abundance of wholesome juice. Besides 
O. Tuna and O. Ficus-Indica, already noticed, O. Engelmanni Salm. 
and 2 or 3 analogous species so abundant along our southwestern © 
boundary are especially noteworthy. Cattle and sheep are very 
fond of the leaves of these piants which are to them food and 
drink during the dry season, so that flocks of sheep fed upon them 
need not be driven to water for several months. 
Several species of Echinocactus may also be mentioned in this _ - 
connection, especially 4. Visnaga Hook. of the central plateau of = 
Mexico and £& Wislizent Engelm. of our southwestern territory ; 
they are called Barrel Cactus from their appearance, the stem be- 
ing sometimes 4 to 5 feet high and 1 to 2 feet in diameter. The | 
pulp of the stem is full of watery juice of a pleasant acidulous taste = 
and has often been welcomed by thirsty travelers. eee 
Many species of Agave with thick fleshy leaves, although | . 
mostly used by Mexicans and Indians for food, contain a large — ae 
_ Proportion of watery juice which can easily be pressed out for — 
drinking. This juice, although not unpalatable, has not the sweet 
. taste which cooking alone develops in it. The Sotol (Dasylirion 
__ Lexanum Sheele) of Texas and northern Mexico shares exactly the 
