XVI. 



C. As a Soil Fertiliser. 

 Prickly-pear has been used to considerable advantage in Ceylon, India, 

 South Africa, and the Mediterranean littoral, as a green manure, and since 

 this method of utilisation involves the destruction of the plant, we submit that it 

 might be employed to a much greater extent in our own country than at present. 

 Our arable Western lands readily lose more or less of their humus— always 

 relatively small in amount — under their climatic conditions. It is considered 

 that this deficiency might be remedied by the use of prickly-pear as a " leaf 

 manure." 



By this procedure, too, there might be added to the soil not only humus 

 but also potash, since succulents, including Opuntias, are always rich in this 

 constituent. A method found to be very satisfactory in India consisted in 

 digging series of wide trenches, almost filling them with broken plants, ^nd then 

 covering the latter with a layer of earth some 18 inches or 2 feet in thickness. 

 Any new growth which may make its appearance should, of course, be removed 

 and buried. After several months the " pear " becomes converted into humus, 

 a valuable addition to the soils there also. 



In many localities the joints are distributed over the field and then 

 turned under, as are other so-called leaf manures. 



Lands in other parts of the world, treated in the ways mentioned, have 

 also given much better crops than untreated areas. 



It is recommended that experiments be conducted in this State, to 

 ascertain in what way and to what extent our naturalised prickly-pears could 

 be suitably employed for similar purposes, especially with reference to the 

 conditions prevalent in our Western lands, which are deficient in the- soil 

 constituent referred to. 



D. As a Source of Alcohol. 



In dealing with the following methods of utilisation of prickly-pear in 

 the industries, the Commission has necessarily in mind the fact that the end 

 in view is the destruction of the pear, and that the undermentioned methods 

 of using what are thus really by-products are looked upon as a means by which 

 the cost of clearing may be lessened. 



Some investigations have been carried out in regard to utilising the 

 whole plant as a source of alcohol, but these have shown that the amount to be 

 obtained is practically negligible, since only about 10 per cent, of the total weight 

 of the green plant consists of carbohydrate, in which the amount of sugar is 

 small, while starch is practically absent. 



The fruit of various species of prickly-pear, however, has been used for 

 alcohol production, especially in the Mediterranean littoral (Italy, Sicily, and 

 Spain), where the manufacture was a commercial success until the imposition 

 of an excise rendered the concern unprofitable. 



The amount of sugar present in the fruit varies in different species, and 

 even in the same species may be increased by cultivation. In the best Mexican 

 varieties, from 10 to 15 per cent, is usually present. It is estimated by some 

 American chemists that about 140 lb. of fruit, with 10 per cent, sugar, is necessary 

 to produce 1 gallon of alcohol. By the addition oj active distillery yeast practi- 

 cally all the sugar was found to have become converted into alcohol in labora- 

 tory experiments. However, in order that the production of alcohol might 

 be carried out profitably, it was considered necessary that there should be the 



