ANIMAL PEODUCTION. 569 



the recordinf? and controlling devices and other accessory apparatus. lu other 

 words, it would be possible, with little additional labor, to adapt the apparatus 

 to the study of additional problems, such, for instance, as the incubation of 

 egj,'s and the changes which take place in curing and storing meat products and 

 cheese, or by making suitable provision for the collection of excretory products 

 and for the comfort of the subjects, it would be possible to adapt the calorimeter 

 to experiments with laboratory animals, should the work of the Department 

 make this necessary." 



ANIMAL PRODTJCTION. 



Ifative cacti as emergency forage plants, J. J. Tpiornbeb (Arizo7ia 8ta. Bui. 

 67, pp. 457-508, pis. 8). — This gives a report of a number of years' experience 

 in planting both spiny and spineless cacti for stock feeding. 



Both the prickly pears and chollas are recommended as emergency forage, 

 the former because they grow more readily from cuttings, sntfer less from the 

 effects of singeing and close browsing than chollas, and are best adapted for 

 planting on the range with the idea of feeding the green vegetative parts after 

 singeing or chopping them. Chollas are useful for their crops of fruit, the best 

 yields being obtained from moderately large plants with a maximum vegetative 

 growth, and should not be singed or otherwise cut back except in extremity. 



Spineless cacti of the Monterey or Chico varieties even in a rabbit-proof 

 fence failed to make successful growth except when irrigated, being injured 

 both by severe winter freezes and extreme heat and drought. 



A key and short descriptions of the more common species of economic cacti 

 and their habitat are given. There are also reports of tests with native cacti, 

 and directions for growing and using cacti for cattle food. 



Nutritive value of cholla fruit, A. E. Vinson {Arizona Sta. Bui. 67, pp. 

 509-519). — Metabolism experiments with cholla fruit, water grass, and the 

 second cutting of alfalfa hay were undertaken with 2-year-old native Merino 

 sheep. The water-grass hay consisted mainly of Chloris cicgans. Water grass 

 was given ad libitum with a small amount of alfalfa, until the animals became 

 reconciled to the experiment. On the sixth day a small amount of cholla fruit 

 was added to the ration, and the quantity gradually increased. It seemed to 

 act as an appetizer, and the animals ate the hay with more relish, due probably 

 to the acidity of the fruit, which is as sour as green grapes and also mucilagi- 

 nous. After the tenth day cholla fruit was given ad libitum, together with 230 

 gm. of water grass and 250 gm. of alfalfa to 1 sheep, and an additional 50 gm. 

 of alfalfa to the second sheep. On the thirteenth day the first sheep left a 

 small residue of hay as well as of cactus, due in part to increasing atmospheric 

 temperature. From this time on the water grass was withdrawn entirely and 

 the alfalfa ration much reduced, although the cactus was supplied ad libitum. 

 The experiment with the first sheep was discontinued on the nineteenth day on 

 account of the heat. With sheep Xo. 2 the experiment was discontinued on the 

 twelfth day for the same reason. 



There was a heavy loss in the nitrogen balance for the first 2 days, due to 

 the change in ration from alfalfa to one composed largely of water grass, and 

 also due in part to the restraint and unrest caused by the harness and other 

 apparatus. From the eighth to the fourteenth day, with increased cactus 

 ration and a restricted supply of alfalfa, the nitrogen income was in excess of 

 the nitrogen outgo. During this period, except on the ninth day, 4.85 lbs. of 

 cholla fruit was placed before the animals daily, so that on those days the 

 animals would probably have eaten more had it been accessible. 



