Vol. VIII. Xo. 198. 



THE AGRICULTUKAL NEWS. 



377 



An Aid in Selection and Breeding. 



In the American Naturalist, July 1909, the difti- 

 ■culties that are met with liy breeders of plants and 

 animals are discussed, with a view to suggesting 

 methods for minimizing them as far as possible. 

 .Among these, the proposal is made to adopt a system 

 of 'selection index numbers', for use when it is desired 

 to improve more than one characteristic of the plant 

 or animal under experiment. In such index numbers, 

 the values of a series of important characteristics 

 would be combined, and they would not only prove of 

 value to breeders, but to judges of stock, as well. 



The Imperial Malaria Conference. ■ 



The Imperial Malaria Conference, which has just 

 finished its sittings at Simla, has made its chief con- 

 clusions and recommendations under the following 

 heads: — (1) the appointment by the Government of 

 India of a Scientitic Investigation Committee, which 

 ■will work together with special organizatiorf in "ach 

 province, in investigations relating to (a) the distribution 

 of malaria in India, (b) the ways in which it originates 

 and spreads in different districts, and (c) the effects of 

 quinine and other remedies; (2) practical measures, 

 including (a) the discovery of a cheap and effective 

 means of destroying Anopheles, (b) minor drainage 

 operations, (c) the restriction of cultivations, such as 

 that of rice, in towns where these give rise to Anopheles, 

 • (d) th^! use of fish against mosquitos, (e) the use of oil 

 for small collections of water in places that can not be 

 filled up; (8) (a) that means be taken to spread knowl- 

 edge among the people regarding malaria, and the 

 measures which it is possible to employ against it, 

 (b) that the subject be taught in schools; (4) that local 

 governments should be invited to assign funds annually 

 for the matters of the investigation and prevention of 

 malaria. 



The Tonkin Rubber Tree. 



A paper appears in the Comjotes liendiis 

 de I'Acadein ie des Sciences, Paris, which gives an account 

 of a rubber tree which is found in Tonkin called Teonon 

 (Bleekrodca tnnkinensis). The latex of this plant 

 contains a high percentage of a rubber which is not very 

 inferior to Para rubber. It grows well on soils wliich 

 do not contain much water, but on which rain falls after 

 prolonged drought. This ability to stand dry conditions 

 for some time arises from the fact that the roots are 

 swollen and store water, and that there are external 

 mineral incrustations on the leaves, which prevent 

 excessive transpiration. 



The swellings on the roots vary in size, being 

 largest in calcai'eous soils. They grow along the length 

 of the root, and from them smaller roots are given off. 

 Though they are round and smooth when young, their 

 form changes as they become older, and a layer of cork 

 forms on the outside of them. This is cracked through 

 as the swelling increases in size, and its place is finally 

 taken by another, which remains when growth inside 

 is complete. 



The mineral deposit on the leaves consists of 

 calcium carbonate : it develops in the outer skin, and 

 remains on the surface in the form of clusters. 



^ 1-^^— — 



Lsmon Grass and Citronella Oils in Indo-China. 



A report by the Director of Agriculture on the 

 experiments conducted in Indo-China in 1908 gives an 

 account of investigations with the oils of lemon grass 

 (Cyinhopogon citratus) and citronella grass (Ci/irdjopo- 

 (jon Narddifi). In regard to the former, distillations 

 were made, following the same manner of operation, in 

 the dry and wet seasons. Plants dried by exposure to 

 the air, and not containing more than 13 to IS per cent, 

 of water for the dry season crop, and 20 to 2.5 per cent. 

 of water for that of the wet season, were distilled. The 

 average of the distillations gave a yield of 79 to 85 of 

 oil per thousand leaves in the dry season, and from (J to 

 7 per cent, in the wet season. On the other hand, the 

 oil obtained from the dry season crop appeared to 

 contain a larger proportion of citral; that is, 78 to 80 

 per cent., instead of 70 to 72 per cent. 



In the case of the citronella grass, the leaves were 

 obtained from a plantation made in 190-1, which had 

 flourished without any care on a soil impregnated with 

 salts, and unfit for the cultivation of rice. The plants 

 cut in the period of vegetable growth, before the appear- 

 ance of the first flowers, produced an average yield of 

 16 per cent, from the dried leaves, while the plants 

 which had flowered only gave a yield of 5 to G percent. 

 The flowering stalks themselves only contained 4 per 

 cent, of essential oil. The fact of the partial disap- 

 pearance of the oil from the leaves during the flowering 

 period has been noticed as well in France, in the case 

 of several different esscntial-oil-yielding plants. 



The Sicilian Green Fruit Trade in 1908. 



In 1907-8, a large and rapid fall in the price of 

 green fruit took place, with the result that speculators 

 found themselves burdened with large stocks which 

 they had bought at absurd prices, a dead market and 

 an oversupply of fruit coming in. The result was that 

 they stated that a crisis had arisen in the trade and 

 demanded Government assistance, in spite of the fact 

 that the Messinese importers pointed out that prices 

 had already been lower before, when there was no talk 

 of a crisis. Ultimately the Government passed a law 

 by which a 'Compulsory Association', centralized in 

 in a Green Fruit Chamber, was to be constituted. 

 The exporters had to sell all citrate of lime to this 

 chamber, and also certificates of analysis had to be 

 obtained from analytical chemists employed by it, 

 exportation by individuals being made prohibitive by 

 a tax based on the percentage of free and combined 

 citric acid in the product. The exporters strongly 

 objected to this, as they held that the trade of the 

 island was being crippled, and their livelihood imperilled, 

 for the sake of a few influential speculators. The 

 effect was that the more oppressive clauses of the law 

 were somewhat modified, and the constitution of the 

 chamber altered. Notwithstanding this, it is expected 

 that harm will still be done to the industry, and that 

 the law will not long remain in force. 



