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when they express an opinion, to let us know whether that 
opinion is merely a general and pious one, or whether it is 
based on direct experimental evidence? I think that nothing 
has been a more formidable enemy in the past to the plantation 
industry than expressions of opinion. 
Dr. H. P. Stevens: Mr. President and Gentlemen—This 
subject has been so well covered by previous speakers that 
very little else is left for me to discuss, and most of my remarks 
will arise out of statements and opinions expressed by previous 
speakers. 
The other day the General Manager of the North. British 
Rubber Company expressed the view that a great deal of pious 
nonsense, as he phrased it, has been talked about variation in 
plantation rubber, and it appears to me that there is a great 
deal in what he said. Up to now those who have discussed 
this matter have not appeared to see the necessity of defining 
what is meant by ‘‘ variation’’ and what is meant by ‘‘ planta- 
tion rubber.”’ Dr. Schidrowitz has just given us a definition 
of variation which I was very pleased to hear, and which, 
generally, I should like to endorse. Rubber may vary in a 
great number of ways, and any one of these variations will 
affect the use of the rubber in the hands of the manufacturer. 
However, we have not had up to now, apparently, a definition 
of plantation rubber, and it appears to me that there has been 
too much confusion as to what is meant by this term. Many 
people, speaking of plantation rubber, think only of what used 
to be termed: first latex rubber—that is to say crépe or sheet 
prepared from latex, while others include in plantation rubber 
not only the first qualities, but various grades of scrap, which 
are prepared and worked up in various ways and sent home, 
forming, perhaps, 25 per cent. of the total quantity. Finally, 
there are those who would include in ‘‘ plantation rubber ”’ 
rubbers coming from plantations on the West Coast of Africa 
and other places, which is very often not Hevea rubber at all, 
so that, before discussing the variations of plantation rubber, 
it is very necessary that we should define what we mean by 
plantation rubber. Statements have frequently been made that 
plantation rubber is more variable than Para rubber. Now 
such statements appear to me extremely unfair to plantation 
rubber, because in fine hard Para rubber we have one definite 
variety or grade, whereas in plantation rubber we may have 
a great variety of grades; and for comparative purposes we 
must confine ourselves either to all grades or to one particular 
grade. 
Now Mr. Williams has given us the heats of cure of a 
number of samples of plantation rubber, but I have no doubt 
he would agree that we could get wider variations if we took 
