SCIENCE AND INDUSTRY. 
received until I reached Washington. A copy is forwarded herewith, 
together with a folder entitled, ‘ Food from Cactus.” It will be noted 
that they now make no claim to produce a: food-from the vegetation 
parts of the plants suitable for human consumption, that they are very 
vague and indefinite about the particular species used, and that the 
process of manufacture is covered by letters patent. 
The price quoted is 30 dollars per ton, which would be equivalent 
to £6 5s. in normal times, and something like £9 at the current rate of 
exchange. This seems much too dear for a material which has a - 
greater resemblance to wheat or oat straw than to any other well-known . 
foodstuff, and about whose palatability and digestibility so little is 
known. ‘They do not at present separate the fibre, but recover a 
trifling amount of potash from the ash of the spines and a small quan- 
tity of various “ juices” whose commercial value is not stated. 
While in Washington I had an interesting interview with Mr. 
David Griffiths, of the Federal Department of Agriculture, with refer- 
ence to various aspects of the Prickly Pear problem. He has, perhaps, 
had a wider experience of the Prickly Pear in the United States than 
any other man. 
Mr. Griffiths considers the Prickly Pear a great national asset,’ 
especially in the drier south-western States, and all his efforts have 
been in the direction of preserving the pear and encouraging its spread 
and growth rather than its destruction. On being asked why Opuntia 
inermis and other species had become such pests with us, he expressed 
the opinion that it was mainly because in Australia the various pears 
seed so freely and the seed germinated so readily owing to the abundant 
summer and autumn rainfall and the absence of severe winters. Even 
in Southern Texas, which may be regarded as the natural home of the 
pear, the seed rarely germinates owing to the erratic rainfall, and con- 
sequently the various species spread only vegetatively. In his long 
experience, only twice in Southern Texas and once in California, has 
the Prickly Pear seeded freely and germinated readily, and that with a 
rainfall of 5 inches in September (equivalent to March in Australia), 
Even then the plants did not grow to any size. He estimates that 
Southern Texas carries twice as many cattle as if the pear were not 
there. Cattle eat most of the species without treatment of the prickles, 
although they attack them more eagerly when the spines are singed off. 
He quoted the case of a herd of dairy cows from Texas which got noth- 
ing but prickly pear as “roughage,” together with a certain amount 
of “ concentrates ” for over two years, and did remarkably well. There 
are no fewer than 200 species in Mexico and Southern United States of 
America of economic importance for feeding, although the most useful 
sorts are about a dozen closely-related species—O. cyanella, O. alto, O. 
gomme, &e. 0. ellisiana is the hardiest spineless form, but the spineless 
. varieties are not nearly so hardy or prolific as the spiny forms. 
Mr. Griffiths was not in favour of concentration of Prickly Pear, as 
it is difficult and expensive to get rid of the water, and the product 
does not seem palatable to stock after desiccation. He, too, had the 
impression that all the cactus products companies had gone out of 
business. » He drew my attention to the work of a Japanese investigator 
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