614 RUBBER 



by monkeys is purely wanton. " They enter an estate, 

 and break off the young shoots and small branches of 

 younger trees and then clear back to the jungle. No 

 efficient remedy is known." 



MOLLUSCS. 



Coming down in the scale of life, I must record the 

 objectionable habits of certain Molluscs species of 

 slugs. These creatures were first brought to my notice 

 in 1905, when specimens were submitted to me with the 

 complaint that they frequented recently tapped Hevea 

 trees, and imbibed the latex as it oozed from the cuts. 

 This habit resulted in an appreciable diminution of the 

 scrap rubber that could be collected after tapping. It 

 seemed hardly credible at that time that any animal could 

 digest liquid rubber. But some of the living slugs were 

 provided with a saucer of rubber milk, and quickly proved 

 the truth of the assertion by commencing to lap it up. 

 One of them drank for about ten minutes. It is quite 

 conceivable that many pounds of rubber may be lost in 

 this manner. The fact that the slugs suffered no incon- 

 venience from this diet lends colour to the theory that 

 Hevea latex contains no rubber as such, but that the 

 caoutchouc is elaborated only at a later stage during 

 the process of coagulation. The digestive juices of the 

 animal possibly prevent this elaboration. Little more 

 was heard of this slug for several years, when it re- 

 appeared in a different role as a serious pest of young 

 rubber trees by systematically eating off the growing 

 points. When the terminal bud is destroyed the plant 

 sends out a series of fresh shoots immediately below the 

 point of injury. These, in their turn, are eaten off, and 

 fresh efforts are made by the plant, only to be foiled 

 every time by the slug. The result is that growth is 

 completely checked so long as the slugs are about. If 

 the damage is allowed to continue a permanently stunted 

 habit may be induced. 



The particular slug that is responsible for this 

 damage in Ceylon has been identified as Marisella 

 Dussumieri. Its habits are nocturnal. During the day- 



