8 MISCELLANEOUS PAPERS. 



The investigations have been conducted in cooperation between 

 the Office of Farm Management Investigations of the Bureau of Plant 

 Industry and the Agricultural Experiment Station of New Mexico 

 for the purpose of determining, if possible, the extent of variation and 

 the nature of the food constituents of the different species wliich are 

 likely to be utilized as food for stock. The plants are grouped under 

 tlu-ee general headings — prickly pears, cane cacti, and miscellaneous — 

 the first group being by far the most important, though the second 

 is largely utilized in sections where its different representatives grow. 

 Three or four members of this group have been fed to stock with 

 more or less success. The third group consists of miscellaneous 

 species fi-om other cactus genera, which on the whole are but little 

 utilized as stock feed, although it is clearly shown that some of the 

 species have been fed in rare instances. The interest in this group is 

 largely a matter of comparison with the others. 



Details of the investigations are published in Bulletin No. 60 of 

 the Agricultural Experiment Station of New Mexico. 



THE SAMPLES OF CACTI ANALYZED. 



Considerable importance is attached to the method of sampling, 

 it being recognized that uniform samples of such succulent and vari- 

 able plants are difficult to secure. It appeared more logical, there- 

 fore, to describe the samples in such a way as to give other investi- 

 gators and the reader an accurate idea of the portion of the plant used 

 in the chemical analysis. The sample is indicated by a formula — 

 for example (2-1-4-3-5) 3 — m wliich the left-hand figure indicates 

 the number of terminal joints, the second number from the left the 

 number of joints next to the terminal joint, and so on, the figure 

 outside of the parentheses indicating the number of plants from 

 which the sample was collected. All samples were forwarded to 

 the laboratory in tin cans from which a minimum of evaporation 

 took place. They were prepared by first being sliced open, so as to 

 expose a maximum of cut surface, and dried by artificial heat at a 

 temperature of not more than 70° C. The spines were then singed 

 off by a small flame of complete combustion, care being taken neither 

 to deposit combustion products upon nor injure the specimens. In 

 the analyses the methods of the Association of Official Agricultural 

 Chemists were followed, with the exception of a few modifications 

 in the determination of certain ash constituents. 



WATER CONTENT. 



A collection of samples for chemical analysis was begun in 1904, 

 and a fairly complete set was secured during that year; but, owing 

 to the uncertainty d\ie to the analysis of single samples, these were 

 nearly all duplicated in 1905, in most cases from the same localities. 



102—1 



