E. J. BUTLER 33 



rubber, and we can only hope that new diseases will be kept from entering these 

 areas as far as possible, or that, if they do enter, the natural barriers to their 

 spread will prove sufficient to protect India against them. 



It follows from this that India should be prepared to list parasites at the 

 reasonable request of Ceylon or the Federated Malay States, even though their 

 host plants aie not of importance to India. We might be asked to list a cacao 

 disease, though the plant is but little grown in India, because it is a valuable 

 crop in Ceylon. In such cases it might save trouble to stop cacao imports 

 altogether, since they are probably quite unimportant. We should, of course, 

 list any rubber disease that these colonies wanted to keep out, and would expect 

 them to reciprocate by listing any diseases we did not want to get. 



The proviso that only such diseases may be listed as are destructive or 

 at least very harmful, leaves out of account the known facts of variation in 

 virulence already referred to. Under it, it is probable that the chestnut bark 

 diseasa could not have been listed, since it is said to do relatively little damage 

 in China and Japan, whence it came. In preparing lists it will be wise to 

 include all such diseases as there is reason to fear, from experience with allied 

 parasites, may develop accentuated virulence if transferred to a new area, even 

 though they are not very harmful in their original home. For the present, 

 special regulations to deal with such diseases outside the Convention would 

 have to be made, but it is to be hoped that they will ultimately be allowed 

 to come under its scope. When a new crop, such as rubber, is introduced, 

 there should be no hesitation in attempting to keep out every disease that it 

 suffers from in its native home, which has dangerous potentialities, even though 

 it may not actually be known to cause appreciable injury. 



It has already been mentioned that certain diseases can be introduced 

 on seed. Seed is frequently conveyed by post and there is no machinery for 

 restrictive measures which could prevent dangerous importations by this 

 road ; seeds are expressly excluded from the Convention. In the United 

 States Quarantine Act of 1912, nursery stock which is subject to restrictive 

 legislation is defined to include seeds of fruit and ornamental trees or shrubs, 

 but field, vegetable and flower seeds are exempted from the regulations, though 

 it is provided that the latter may be extended to include exempted articles 

 by the Secretary of Agriculture in case of need. Also the United States Post 

 Office Order of July 1st, 1913, renders nursery stock unmailable in the 

 international Parcels Post, unless addressed to the United States Department 

 of Agriculture. Hence the United States has gone further than the Eome 



3 



