RUBBER PLANTING 173 



all ordinary tests. In fact, there is every reason for 

 believing that in the future the highest plantation 

 grades will share with hard Para the distinction of 

 representing the highest standard of quality, even if 

 they do not oust the American product from its present 

 position of superiority. 



As regards chemical purity, plantation rubber already 

 surpasses any wild kind. It is therefore preferred by 

 manufacturers to any wild rubber for the manufacture 

 of rubber solutions and for waterproofing. 



Defects and Blemishes. 



Complaints are not uncommonly made of the 

 appearance of spots and discoloured patches on the 

 rubber turned out of the factory. In fairness be it 

 remarked that such complaints are much less common 

 than formerly. Fetch states that the chief organisms 

 concerned in the spotting of rubber biscuits appear to 

 be bacteria and yeasts. Blood red spots sometimes 

 appear. These have been attributed to the action of 

 Bacillus prodigiosus, the microbe responsible for the 

 so-called bleeding miracles. Brown and black patches 

 may be due to the attacks of other bacteria. Dis- 

 colouration may usually be prevented by attention to 

 perfect cleanliness at every stage of preparation. All 

 utensils which are brought in contact with the latex 

 should be frequently scalded with boiling water, and the 

 factory itself should be kept scrupulously clean. The 



