114 
Bauer* in the same year explained the scientific principles on 
which the selection of Hevea should be based. He also advocated 
the introduction of fresh types from Brazil, in addition to selec- 
tion from among the Hevea plants cultivated in the East Indies. 
There are thus two points of view under consideration :— 
1. Selection from the trees at present in the East Indies. 
2. Importation of new types from Brazil. 
The first method would mean tke improvement of the existing 
plantation Hevea, for a better stock of plants would be raised by 
the selection and cultivation of a healthy and high-yielding strain 
0 ants. 
The prospects of selecting a good strain from local trees are 
14 years old. In 1917 the selected tree gave on an average 
5 grammes of latex per day, and in 1918 the yield was 70 
grammes. (Average of 12 monthly observations.) This tree had 
gradually raised from the 
crossing high-yielders during many generations. 
- Vegetative Selection. The good qualities ‘of high-yielders 
may be perpetuated by grafting and by means of cuttings. 
Generative Selection.—Seed selection is on the whole the 
better method ; but it is essential that both the parents should be 
high latex-yielders. The crossing of good-yielders can be carried 
ties. Bauer recommends nurseries composed of t 
good parent trees of both sexes. 3 biped ta is 
_A good method of forming seed nurseries is by grafting high- 
yielders on strong year-old stems. Stocks grafted with two 
* Die Fortschritte der Vererbungsf i ij 
She U gstorschung und ihre Bedeut f 
ie sr pai tropischer Kulturpflanzen besonders der Kautuskeklsasell 
aa report of the Internat. Rubber Congres. Batavia, 1914, appendix 3, 
