. 
SCIENCE AND INDUSTRY. 
Professor Watt, of the University of Sydney, has made inquiries into 
the subject, and has reported that the process was evidently successful 
in removing the fibre, the prickles, and the tannin substances, but that 
the “grain” (the main product) has not a high feeding value, being 
poor in protein and having a calorific value lower than wheat straw. 
Professor Watt also stated that the two species chiefly used in America 
were quite different from the pear which has established itself over 
such a huge portion of the Commonwealth. As Professor Watt is 
visiting Great Britain shortly, travelling by way of the United States, 
he has been asked by the Institute to make full inquiries into the 
utilization of the pear as a food for stock. 
THE GUAYULE RUBBER PLANT. 
Some time ago the suggestion was made to the Institute by Mr. W.- 
Ham, of the University of Adelaide, that research experiments might 
be carried out into the characteristics of Guayule (Partheniwm argen- 
tatum) for rubber production. Mr. Ham pointed out that the plant 
was extensively grown in the arid portions of Mexico, and that large 
quantities of commercial rubber were now being made annually from 
this plant. In consequence of these representations, inquiries were 
addressed to the Bureau of Plant Industry of the United States 
Department of Agriculture for all information on the subject, with a 
view to a preliminary consideration of the question. Guayule, it 
appears, is a small woody shrub varying from 8 to 40 inches in height, 
with an average of 2 feet, having a much branched stem. It occurs 
over the “bush prairies” of North Mexico, and extends into Texas, 
New Mexico, and Arizona. The small leaves are greenish and silvety 
grey, as also are the younger twigs, which, as the age of the axis 
advances, change to light, then to dark ashy grey. The winter appear- 
ance of the plant is strikingly different from the summer appearance. 
In the winter, the leaves, saving those forming small clusters at the 
tips of the twigs, have fallen, leaving these bare. In summer, the new 
growths are clothed with leaves of maximum size, in which the green 
colour is more apparent. At this time, the flowers are borne in loose 
clusters on slender stems, and crown the plant with a profusion of small 
yellow blossoms. These are arranged in heads, each head resembling 
a small daisy, and capable of forming, at most, five seeds. Usually, 
some of these do not develop. A curious manner of development results 
in the association with the seed of a large amount of chaff. Guayule 
is distinct from most other rubber-producing plants, in that its bark 
contains no latex; rubber being in the cellular tissue of the epidermis, 
and, to a small extent, in the branches and leaves; the blossoms being — 
without traces of rubber. The amount of rubber in the topmost 
branches is very slight, but increases towards the roots. 
THE GUAYULE RUBBER INDUSTRY. 
In a special report written for the Bureau of Foreign and Domestic 
Commerce, United States of America, in April, 1919, it is pointed out 
that the most’important guayule districts command good railway 
facilities, although there are large areas whose exploitation is difficult 
TO 
