THE AMERICAN BOTANIST 97 



Resin. It has been discovered in Mexico, according to 

 C. E. Guyant, that an analysis of the dead bark of Cereus 

 thurberi Engelm. indicates that the resin content is sufficient 

 in quantity and easily enough extracted to make its utilization 

 practicable in cactus regions of this country. 



Whitewash. We are informed by F. W. Goding that in 

 Uruguay the leaves of a common cactus, (probably an 

 Opuntia), are sliced and macerated in water for twenty- four 

 hours, producing a creamy solution, to which is added lime, 

 and the whole well mixed. When this is applied to any sur- 

 face, be it of wood, brick, iron or other material, a beautiful 

 white appearance is produced which withstands the action of 

 the elements admirably. This practice is also quite common 

 in northern India, according to Johnston and Tryon. The 

 particular cactus here used is Opuntia iiciis-indica Mill. In 

 both cases, the part played by the cactus is the supplying of a 

 mucilaginous substance which causes the whitewash to adhere. 



Miscellaneous. The pulp of Nopalea sp. is said to clear 

 water of impurities or settle coffee in the same manner as the 

 white of an egg, according to Bois. The writer has used cactus 

 spines many times for toothpicks, also for dissecting needles, 

 for both of which they were very satisfactorv. 



