AGRICULTURAL BULLETIN 
OF THE 
5TRAITS 
AND m 
FEDERATED MALAY 5TATE5. 
No. 10.] 
OCTOBER, 1911. 
[Vol. X 
ON THE OCCURRENCE AND NATURE OF SPOTS 
ON PARA SHEET AND CREPE. 
A Preliminary Note. 
By Keith Bancroft, b.a. 
Since the market value of rubber is considerably influenced by 
its appearance, it is desirable that there should be no deviation from 
the normal colour when the product is placed on the market. The 
occurrence of spots of different colours =t>n sheet and crepe lowers the 
market value considerably. Pink or red, bluish and black spots 
were found to occur first on sheet in this country and then on crepe. 
During this and the previous year spotted sheet and crepe have been 
reported from several plantations, and the quantity of spotted rubber 
appears to be on the increase. 
Similar red spots have been reported from Borneo by Brooks 
where they were said to occur in some quantity, as many as 288 
being present in one square foot in some samples. Brooks claims to 
have obtained an organism in strong crimson culture on bread and 
agar-agar which appeared to be Bacillus prodig iosus ; and he concludes 
that the organism was introduced into the latex by the use of pool 
water. 
Petch also reports the occurrence of Ted and black spots on 
“ biscuits ” in Ceylon, but says that he^is unable to associate them 
with mircro-organisms. 
Samples of a pink spot occurring in this country were sent 
to England and were identified first as being due to a yeast and 
later to Bacillus prodigiosus .* 
