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A FORTNIGHTLY REVIEW 



OF THE 



IMPERIAL DEPARTMENT OF AGRICULTURE FOR THE WEST INDIES. 



Vol. XI. No. 270. 



BARBADOS, AUGUST 31, 1912. 



Pkice Id. 



CONTENTS. 



Pagk. 



Pagi 



Adsorption of Certain Suli- 

 stauces by Starchus 



A'^riculture in Ceylon, 

 1910-] I 



Book Sliflf 



Chlorr.codon Root Oil ... 



Cotton Notes : — 



Cotton-Growing in Rus- 

 sia 



Poisoning by Cotton 



Seed Afeal 



West Indian Cotton... 



Department News 



Depart mental Rejjorts ... 



Fruits, Making Models ni 



Gleanings 



Hcvea, Characteristics of 

 a Hybrid 



Insect Notes : — 



Report on a Visit to 

 St. Kitts, Part I ... 



Market Reports 



Nitrates, Eni|>loyment by 

 Plants for Nutrition 



2,S1 



283 

 286 

 280 



278 



278 



278 

 274 

 277 

 276 

 284 



275 



282 

 288 



280 



Nitrogen from the Atmos- 

 phere 279 



Notes and Comments ... 280 



Plant Growth, Stimula- 



tiin of 273 



Pruning Sea Island Cot- 

 ton 



Siipucaia Nut 



Silkworm Industiy. 1912 



Studi-nts' Corner 



Sugar Industry:. — 



The Cost . of Growing 

 Sugar-cane in Cuba... 



Trade and .4igriculture of 

 St. Helena, 1911 ... 



Vegetative Propagation, 

 Continued, Changes 

 in Plants through ... 



Virgin Islands and the 

 Canadian National 

 Exhibition 



West Indian Products ... 



281 



287 

 281 

 285 



285 



281 



283 



287 



The Stimulation of Plant Growth. 



T is usual to regard the function of manures 

 as consistins; in the direct provision of food 

 I to the plant: the agriculturist emploxs them 

 because he considers that they snppl}' substances 

 required by the plant, in which the soil is lacking 

 either on account of its peculiar nature or because the 

 amount of those substances has been lessened by the 

 growing of previous crops. Though the subject requires 

 much further investigation, there appears to be little 



doubt that this is the right view of one of the func- 

 tions of manures: an account that gives the chief obser- 

 vations and arguments that are in favour of this view 

 has appeared previously,* and may be consulted if 

 a sumuiary of these is desired. 



The question has been raised, however, as to the 

 extent to which manures may simpi}^ stimulate the 

 growth of plants; that is to .say it has been asked if 

 manures are capable of causing changes to take place 

 in plants, which result in increased growth, without 

 necessarily acting as providers of food. Invi stigationsf 

 have been undertaken recently that appear to consti- 

 tute a preliminary step in obtaining an answer to the 

 question, and it is the purpose of this article to give 

 a general account of the work and of the conclusions 

 to which it has led. 



It has often been noticed that certain leaves, such 

 as those of the cherry laurel (Primus Lauroceramifs) — • 

 a plant indigenous in Europe and Asia, although they 

 do not possess any perceptible odour, under ordinary 

 conditioEs, emit the vapour of oil of bitter almonds, 

 as well as prussic acid, when they are crushed; the 

 most delicate tests for this acid do not indicate its 

 presence when the leaf is allowed to remain whole, in 

 ordinary air. The same result as that obtained by 

 crushing may be brought about in other ways, 

 such as subjecting the leaf to the vapo"r of 

 chloroform and many other volatile organic substi'ices, 

 including hydrocarbons, alcohols, ethers and es-ential 

 oils; non-volatile substances, too, produce the effect!, 

 and the less soluble among them do this more readily 



* AgriculUral News. July 6 and 20, 1912, pp. 209 and 225. 



t Profe.ssor Henry E. Arm.strong, F.R.S., in the Journal 

 i.f thr Roynl Hortknltural Socirfy, Vol. XXXVIII, p. 17 

 (July 1912). 



