AGRICULTURAL BULLETIN 



OF THE 



5TRAIT5 



AND 



rCDEBATED riALA/ 5TATE5. 



No. 10.] OCTOBEE, 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 on 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 prodigiosus ; and he concludes 

 that the organism was introduced into the latex by the use of pool 

 water. 



Fetch also reports the occurrence of red 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. 



