EVENING DISCOURSES. 



FIRST EVENING DISCOURSE 

 Friday, September 2, 1932. 



PLANT PRODUCTS OF THE EMPIRE 

 IN RELATION TO HUMAN NEEDS 



BY 



SIR A. W. HILL, K.C.M.G., F.R.S. 



When we come to consider human needs in the light of products derived 

 from plants, it is interesting to notice how ' relative ' they are and how they 

 tend to change in the course of time. 



Those plants which yield food, beverages, spices and drugs in particular, 

 as well as those yielding timber for construction and fuel, fibres for clothing 

 and cordage, etc., and fodder for cattle, have always been of primary and 

 universal importance, and may be regarded as among the essential needs of 

 the human race. 



There are, however, constant changes and new developments in human 

 needs as regards the vegetable kingdom, which to some extent may be 

 regarded as artificial or induced, since they are concerned with some of the 

 vagaries or artificial needs of our modern civilised conditions. 



As a contrast with the primitive conditions of early life in Britain, when 

 our ancestors were content to clothe themselves with skins which they dyed 

 with woad, the modern desire for gramophones may be cited, for some 

 gramophone needles are made from the spines of a Prickly Pear (Opuntia) 

 and are sold in packets for the purpose. Opuntias, as is well known, have 

 overrun much of N.E. Australia since they were introduced there from 

 America. Then there is the desire of some youths to appear well dressed 

 by the addition of a stiff white collar, which may be composed of celluloid. 

 For the manufacture of these articles, which do not need the washtub, large 

 quantities of camphor are employed in addition to cellulose derived from 

 vegetable sources. 



Another somewhat deplorable human need, at any rate when carried to 

 such excesses as we see it in America, is the present induced human need — 

 or rather craving — for newspapers which is resulting in the destruction of 

 the magnificent forest trees of the Empire in Canada and Newfoundland. 

 Yet another human need of quite recent growth, depending on the vegetable 

 kingdom and so largely supplied by the British Empire, is that of motor 

 tyres, and every sort of rubber article made from the rubber contained in the 

 latex of Hevea hrasiliensis . This Brazilian plant was first sent out through 

 Kew to the Far East ; and to this introduction our propensities for scrib- 

 bling may perhaps be attributed, since our modern human need for fountain- 

 pens is satisfied from our rubber supplies. 



