83 



regard to the value of prickly-pear as a reserve 

 fodder against times of drought. He recapi- 

 tulated the results of Griffiths and Hare, and 

 gave botanical details regarding many of the local 

 species. 



In the same year J. J. Thornber, of the 

 University of Arizona, published the results of 

 his efforts in an article on "The Native Cacti as 

 Emergency Fodder Plants" (1911). The native 

 species were found to be able to withstand the 

 rigorous climate of Arizona much more satisfac- 

 torily than the various spineless forms experi- 

 mented with. It was shown that sheep, if fed on 

 cactus alone, undergo nitrogen starvation, but 

 when the prickly-pear fodder was balanced by 

 the addition of a small amount of food rich in 

 protein, then the ration had a decided nutritive 

 value. These plants are looked upon by him solely 

 as an emergency fodder and as a range crop, 

 not as a farm crop. Hence the planting out of 

 ChoUas (Cylindropuntia) and prickly-pear 

 (Platyopuntia) in the open country in Arizona 

 was strongly advised. Details as to the prepara- 

 tion of each for fodder were given, singeing 

 being the method recommended. 



When visiting Arizona, the Commission's 

 observations led to the conclusion that certain 

 indigenous species of Cylindropuntia — the 

 ChoUas — supplied a very considerable part of 

 the dietary of. cattle who fed on the abundant 

 green perennial fruit, areas in which ChoUas 

 were abundant and in which there was little 

 if any grass being fenced off for grazing pur- 

 poses. 



The nutritive value of ChoUa fruit (0. ful- 

 gida)* was investigated by Dr. Vinson (1911), 

 who used sheep as experimental animals. He 

 found that as a ration for maintaining sheep in 

 a fair state of nutrition it would be necessary 

 to supply an animal with an amount of fruit far 

 beyond its capacity, at least 45 lb. daily being 

 needed. Besides, this would contain excessive 

 mineral salts. The fruit alone appears to be 

 inadequate to maintain the nitrogen equilibrium 

 for any lengthened period. The addition of half 

 to three-quarters of a pound of lucerne hay to a 

 diet of 6 or more lb. of choUa fruit would 

 probably preserve life in the case of a 120-lb. 

 sheep, and there would perhaps be some gain 

 in weight. It was suggested by him that similar 

 results might be obtained with range cattle by 

 using Quantities increased proportionally to the 

 live weight — i.e.. about 4 to 6 lb. alfalfa or its 

 oquivalent and 50 or more lb. of ehoUa fruit daily 

 (p. 518) . It was found that sheep in confinement 

 could not be forced to eat other forms of cactus 

 except the fruit, but ate the latter quite readily 

 when the supply of lucerne was limited. Range 

 cattle eat considerable quantities of cactus, 

 especially their succulent acid fruits. 



The information obtained by the Commission 

 from various sources pointed to the fact that 

 nrickly-pear was generally regarded as a nuisance 

 if abundant, and as a plant possessing some 

 value only during times of drought when other 

 stock food was scarce. The Mexican teamsters 

 in Texas are in the habit of giving cactus to their 

 animals, which generally have to find most of 

 their own food. Stockmen occasionally make use 

 of the pear after burning off the spines by means 

 of a brushwood fire or a torch. In one place, 



* 0. imbricata, which occurs sparingly in New South 

 Wales and Qweeppland, is allje4 to O, fulgida. 



prickly-pear was seen to be cultivated, the plants 

 being singed and dairy cattle then turned in to 

 feed on the cactus as a roughage. This was at 

 Mr. Sinclair's farm near San Antonio, and it 

 was here that Dr. Griffiths carried out some of 

 his experiments. 



The experience in the United States in regard 

 to using priekly-pear as a stock fodder is thus 

 fairly similar to that in Australia, though the 

 cactus there is relatively less abundant, being 

 largely controlled by climate and to a consider- 

 able extent by various natural enemies.* 



Farmers get rid of the cacti by cutting them 

 down, and either burning them after partial dry- 

 ing, or else ploughing them into the soil. 



UTILISATION FOR THE MANUFACTURE 

 OF ALCOHOL. 



Professor Hare and his colleagues, S. R. 

 Mitchell and A. P. Bjerregaard, have published 

 (1909) a paper dealing with the question of 

 obtaining denatured alcohol from Opuntias. They 

 found that about 10 per cent, of the total 

 weight of a prickly-pear plant consisted of carbo- 

 hydrates, mainly plant mucilage and soft eeUu- 

 lose tissue, there being no starch except in spring. 

 Sj'nce the amount of sugar present at any season 

 was quite small, there was consequently very little 

 material available for the production of alcohol, 

 and hence the possibility of obtaining that pro- 

 duct commercially from the plant as a whole was 

 negligible. 



In regard to the utilisation of the ripe fruit 

 for the manufacture of alcohol, it is pointed out 

 that the fruits of many species are used largely 

 by Mexicans as articles of food, their value being 

 due to the high sugar-content — mainly dextrose — 

 which in the best varieties amounts to from 10 to 

 15 per cent. Where prickly-pear (0. Imdhei- 

 meri) had been cultivated, as near San Antonio, 

 Texas, the fruit obtained averaged 8 tons per 

 acre, from 10 to 12 tons being obtained some- 

 times; but in New Mexico the plants when wild 

 did not grow sufficiently close to make fruit col- 

 lection for alcohol manufacture profitable. 

 Besides this, the cost of hauling the fruit to a 

 distiUery would have to be considered. Then, 

 again, it was estimated that if fruits have 10 per 

 cent, of sugar about 140 lb. of fruit would be 

 required to produce a gaUon of alcohol, and this 

 would necessitate considerable labour being used, 

 only hand labour being available in New Mexico. 



It was found that various types of yeast could 

 be employed, but substances other than alcohol 

 were also produced, e.g., acetic acid, &c., whereas, 

 by using pure cultures of an active distillery 

 yeast, practically aU the sugar was converted into 

 alcohol. The details of the method are described 

 (pp. 36-40). The addition of Pasteur's mineral 

 nutrient did not increase the amount obtained. 

 It was suggested that the sterilisation of the fruit, 

 or the fruit-juice, foUowed by cooling before add- 

 ing the ferment, would probably be beneficial. It 

 was found that the fruit- juice if evaporated to a 



* Mr. Came { 1913, p. 975) has recently pubUshed some 

 observations made during a visit to the TJmted States 

 He beUeves that the spread of pnckly-pear there depends on 

 a sufficiency of moisture and an absence of frosts. The fact 

 that grass-fires are much less common now than formerly 

 has led to a much more rapid spread of cacti. Distnbution 

 by cattle is also a factor in the spread Mr. J. D. Mit°heU 

 who accompanied the Commission m Texas, held the same 

 ^ews regarding the cause of the increase » OpuntiM is 

 pwts of that State, 



