ToL. XI. No. 267. 



THE AGRICULTURAL NEWS. 



23.3 



Experiments on Chlorosis. 



Chlorosis is a conditJDn in plants in which for some 

 reason or other the green colouring matter is either 

 partially or entirely absent. An investigation for the 

 purpose of obtaining information concerning the causes 

 of chlorosis is described in the Coriqjtes Rendus de 

 i' Acade'mie des Sciences (Paris) 1911, p. 902. In this, 

 experiments were conducted in which maize was grown 

 in nutrient solutions, some of which were complete and 

 some incomplete, the omissions fmm the latter con- 

 sisting of such constituents as manganese, iron, sul- 

 phur, silicon, lime and chlorine. 



The absence of sulphur and ii-on resulted in inter- 

 ference with development, and chlorosis; the effect of 

 the absence of the sulphur was shuwn more quickly 

 than th.it from the want of iron. Observations on the 

 development and constituents of the leaves showed 

 that the cause of chlorosis is, as was to be expected, 

 interference with nutrition. The condition could 

 always be corrected perfectly by supplying the plant 

 with the element that was wanting. The green colour 

 could also be restored by pouring dilute ammonium 

 suliihate on the leaves. 



Chlorosis was n<it found to be caused by the 

 absence of chlorine, magnesium or silicon. 



Black Blight in Grenada. 



At a meeting of the Agricultural Board of Grenada 

 held in March last, the Superintendent of Agriculture 

 was asked to explain the reasons for the reduction to £.50 

 of the amount on the Departmental Estimates for experi- 

 mentation in connexion with black blight. It was 

 stated in reply that such excellent results had beea 

 obtained through the use of imported parasitic fungi 

 that a very small part of the sum of £100 that had 

 been vnted previously was actually spent. It was 

 therefore considered that half that sum would be ample 

 for the work of the coming year. 



This fact forms a very effective illustration of the 

 usefulness, under certain conditions, of parasitic fungi 

 in combating the scale insects that are followed by 

 black blighc. The matter is dealt with at some length 

 in the \ast Annual Re'jport (1910-11) on the Grenada 

 Botanic Station. 



At the meeting mentioned it was decided ulti- 

 mately that the sum of £.50 should stand, and that 

 this would be sufficient to provide, as well, a certain 

 amount that might be expended in trials of treatment 

 for the coco-nut palm bud rot. 



The Victoria Museum, Dominica. 



The first annual report of the Directors of this 

 institution was gazetted on May 31, 1912. It 

 shows firstly, that the arrangements for starting the 

 Meseum were made in February 1910, and that 

 Messrs. H. A. A. NichoUs, C.JM.G., M.D., F.LS., 

 J. .lones (Curator of the Botanical Gardens), and E. A. 

 Agar, F.E.S., were appointed by His Honour the 

 Administrator as a Board of Directors of the museum. 



The museum was opened to the public on 

 October 23, 1911, and it was decided that it should 

 be opened on alternate mornings and afternoons to the 

 genei-al public, and at other times for the accommoda- 

 tion of visitors to the island. 



Among those, others than the members of the 

 Board, who are mentioned as having given assistance 

 in connexion with the museum, have been Mr. Hugh 

 Scott, B.A., F.E.S., of the Museum of Zoology of the 

 University of Cambridge, Dr. 1). Thaly. and .Mr. P. W. 

 Jarvis. 



The present contents of the museum, according to 

 the details given in the report, consist mainly of 

 specimens of insects, especially Lepidoptera and Cole- 

 optera; coi-als and land shells; samples of the agricul- 

 tural products of the island; polished specimens illus- 

 trative of the timber resources of Dominica; and 

 a collection of Carib stone implements. Efforts to 

 add to these are being continued, while the economic 

 section is in the charge of the Botanical Department. 



The general public has showed interest in the 

 collections, many specimens among which have been 

 provided by school children. When the museum was 

 opened it contained 1,271 specimens; at the time of 

 •reporting the number had reached 1,501. 



Rubber-Growing in Sumatra. 



The growing of rubber in plantations has become 

 one of the most important industries in Sumatra, and 

 is regarded as being of particular usefulness with res- 

 pect to the development of the east coast of the island. 

 According to a recent report by the British Vice-Con- 

 sul at Medan, dealing with the conditions on this coas:*, 

 about five-eightlis of the capital invested in rubber is 

 British. Better means of communication are reipiired, 

 however, for successful exploitation. The activity of 

 the different companies interested in the matter varies, 

 but preparations are being made by several of them to 

 plant considerable areas in rubber. 



It is not possible to obtain reliable statistics as to 

 the amount of capital invested in the industry, and the 

 area under plantation rubber. Returns are available, 

 however, which go to show that about 130,000 acres of 

 rubber had been planted up to the end of last year; of 

 this, more than 12.5,000 acres was under Hevea Jmcsil- 

 iensis. At the end of the time mentioned, it was 

 estimated that there were fifty British rubber com- 

 panies working in Sumatra, with an issued capital of 

 approximately £5,000,000, and a nominal capital of 

 about £6,200,000. An estimate gives the capital invested 

 by countries other than Great Britain, in rubber-grow- 

 ing in East Sumatra, as the following: Dutch 

 £3,000,000, German £80,000, Belgian £62,000, and 

 Swedish £20,000. . • 



The number of companies that were producing 

 rubber at the time of reporting was about thirty, but 

 most of these have only commenced tapping recently, 

 and on a very small scale. Further estimates show 

 that the export of plantation rubber from the East 

 Coast of Sumatra during 1911 was about 677 tons; 

 of this about 550 'i?ns was sent to London. 



