54 



refined sugar-bearing substance were available, it is possible that 

 for certain soils the application of sugar would become an econo- 

 mically satisfactory treatment. Experiments on this subject might 

 well be carried out in the West Indies. 



There are secondary advantages to be expected from sulphuric 

 acid disinfection which may be of considerable importance in some 

 cases. Under appropriate circumstances a larger germination per- 

 centage is secured, the number of parasites in the soil is reduced, 

 and the well-known effect of disinfection on fertility results in 

 increased growth. Another valuable effect has proved to be the 

 reduction of weeds owing to the greater susceptibility of their seeds. , 



In considering the application of the methods to local condi- 

 tions, it is necessary to emphasize the fact that the results stated 

 have been obtained with the seedlings of a definite group of plants, 

 the conifers. It will be necessary to find by experiment how far 

 they are transferable to the seedlings of unrelated plants. In view 

 of the difference of soils, moreover, such experiments must be 

 carried out in the situation where the seedlings for which it is 

 proposed to adopt the method are raised. 



Some hints are given as to the method of handling the acid. 

 It should always be dissolved by pouring it into the water; revers- 

 ing the process may cause a serious accident. The solution should 

 be made up in wooden or earthen containers and applied with 

 watering cans which have been coated inside with paraffin wax. 

 Boots may be protected by being heavily greased. Wooden con- 

 tainers should be washed out, immediately after use, with water 

 containing washing soda. ^y 7^^ 



PROPAGATION OF HEVEA FROM STAKES. 



On page 251 of the first volume of the Gardens' Bulletin 

 reference was made to the difficulties experienced in propagating 

 Hevea brasiliensis by means of cuttings. Experience in Ceylon 

 and in the Malay Peninsula was quoted; and Mr. Fetch's sugges- 

 tion that Tlnvaites had been deceived when he claimed it to be easy 

 was cited. 



Fresh experiments were then made with cuttings from young 

 twigs, witliout success; and when it happened, in" 1917, that a 

 big wind destroyed many rubber trees in the Economic Garden, 

 stakes Avere cut from them for supports in the yam beds, so that the 

 misfortune of losing many rubl)er trees gave the opportunity of 

 trying propagation from l)ranches 1 — 3 iiu-hes in diameter. 



These branches were cut diagonally with a sharp knife at the 

 end, thrust into the ground, and wired together at six feet in the 

 way whi:'h is seen in Flate VI of the first volume of the Bulletin 

 Xos. 1M2 (opposite p. 394). 



Out of a total of 14S9 stakes so taken, 18, or 1.21%, took root 

 and produced leaves. 



The weather was wet when in January and Februarv the stakes 

 were set m the grouiul. ' j_ jj. Burkill. 



