16 ORNAMENTAL CACTI. 



the plant is totally destroyed. The disease travels inward, toward 

 the center of the plant, following fibro vascular bundles. The colored 

 tissue readily separates from the healthier portion of the plant and 

 is easily removed, but this merely checks its ravages for a time. The 

 disease penetrates every .portion of the plant and in time will make 

 itself manifest again in other orange-colored spots on the surface. 

 It is a contagious disease, and the only hope for saving a collection 

 of plants is to destroy all the infected individuals, preferably by 

 burning them. Many remedies for this disease have been applied, 

 but without success. 



INSECT PESTS. 



The Bureau of Entomology of this Department has investigated 

 cactus insects extensively. The results of this work appear in a 

 bulletin of that Bureau (No. 113), winch may be had upon appli- 

 cation. 



ECONOMIC VALUE OF CACTI. 

 MEDICINES. 



To a limited extent Cereus^ grandiflorus and C. nycticalus have 

 been used in the preparation of certain compounds. Other 

 cacti are known to contain characteristic alkaloids which from 

 their peculiar action on the human system may yet prove of value 

 in treating special disorders. Most notable of these forms is the 

 so-called piote bean or mescal button, also known as the dumpling 

 cactus (Lophophora williamsii and L. lewinii). Since remote 

 times the aborigines of America have used this plant in certain of 

 their religious rites. When the plants are eaten raw, dried or fresh, 

 with water, the optic nerve is so affected that by closing the eyes the 

 user is made to see visions illuminated in the brightest of colors. 

 An alkaloid of this plant has been separated from it and found to 

 contain the same properties. It is not impossible that in time it may 

 be found of value in the treatment of certain ocular disorders. How- 

 ever, no member of the family seems as yet to have yielded a drug 

 that has been used to any considerable extent as a medicine. 



GARDEN VEGETABLE. 



Among the poorer classes of Mexico the very tender growths of 

 Opuntia are eaten raw, made into a sort of salad, or are cooked, as 

 may be desired. There is little to commend this cactus to those 

 having access to the common and more palatable vegetables of the 

 garden. 



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