Vol. XVIII. No. 445. 



THE AGRICULTURAL NEWS. 



151 



that copra to the value of £1,388,418 was exported in 

 the fiscal year ending June 1917, and to the value of 

 £1,905,448 for the year ending June 1918. It is expected 

 that a shortage of copra will be experienced after 1918. 



Previous to 1915 coconut oil was produced in very few 

 factories, and chiefly in the P.V.O. of Manila and the 

 Visayan mills of Cebu. There were also a few small oil mills 

 with modern machinery, and also a certain amount of oil 

 produced in the native villages by the ordinary native hot- 

 water extraction process. 



To-day there are in Manila alone twelve factories, and 

 the value of coco-nut oil exported in the first quarter of 1918 

 was £1,610,000. The coco nut oil mills are making large 

 profits, and new mills are going up rapidly. 



There is considerable optimism for the future of 

 coco-nut growing in the Philippines. The price of copra is now 

 low in proportion to the price of oil, owing to the preference 

 for oil as cargo, and ihe lack cf oil expressing facilities 

 hitherto. 



It is not improbable in fact that there will arise a 

 period of competition among oil mills for copra supplies, 

 which, being limited, are apparently destined to get short, 

 and in consequence the price of copra during that period 

 may be relatively hitiher than that of oil. It is expected 

 that an immediate fairly heavy fall in the American price of 

 coco nut oil will follow the cessation of war, through the 

 feeling of security of future supplies as ocean tonnaiie increases. 

 The present high price of coco nut oil will probably de- 

 cline, but lower freight rates will possibly largely compensate. 

 The general opinion in the Philippines is that the future of 

 the coco-nut oil business is promising, with the expectation 

 that the eventual volume of business will be limited only by 

 available supplies of copra. 



THE HYDROCYANIC ACID CONTENT OP 



GUINEA CORN. 



It has long been known, and the subject has been 

 referred lo in several previous volumes of the Aqrlcuhural 

 News, that a cyanogenetic glucoside is present in Guinea corn 

 {Andropngon sonjhum) in certain stages of its growth. This 

 glucoside is not poisonous by itself, but in contact with an 

 enzyme which is presrntin the plant tissues it breaks up into 

 several compounds, one of which is hydrocyanic acid. It is on 

 account of the formation of this latter substance that Guinea 

 corn fodler acts at times as a poison, and cases of poisoning 

 of cattle by eating Guinea corn fodder are not of infrequent 

 occurrence in some countries, as in the United States and in 

 India, although such ciSirS appear to oosur but rarely from 

 the use of the varieties cultivated in the West Indies. 

 A paper in the Agricultural Journal of India, Vol. XIV, 

 Pa,rt 1, by .Manmathanath Ghosh, M.A., Assistant Professor 

 of Chemistry and Physics, Sabour Agricultural College, gives 

 !in account of trials made to find out the effects of different 

 times of planting, and also of water-logging on the formation 

 of the glucoside in Andn pojon soiy/ium, known in India as 

 'Jowar'. The experiments were undertaken in 191C and 

 repeated in 1917, and in the article referred to the results are 

 set out vfry fully in tables. 



The conclusions reached may be summarized as follows: — 

 T"e time of planting does not appear to have any effect 

 on the formation of the glucoside to which the name 'dhurrin' 

 has been given. With ih'i three sets of plots sown at differ- 

 ent times, and nearly at a month's internal between one and 

 the next, there was no diflference between the first and the 



second set, both as regards the maximum yield of the poisJB 

 or its rate of diminution as the plants grew up, but the 

 third only showed half the raaximum quantity of the poison, 

 though the rate of diminution of the poison was very much 

 the same. 



It therefore appears that while the time of planting by 

 itself has little or no connexion with the formation of the 

 glucoside, yet a crop planted late has a much better chance 

 of producing smaller quantities of the poison on account of 

 the more abundant moisture generally found in the soil at 

 such a time. Dhurrin occurs principally in the leaves and 

 young shoots. There is a very much smaller quantity of it 

 in the stalk, from the time the plant grows to an appreciable 

 height. 



The factors which so far seem likely to bear on the 

 production or otherwise of the glucosides are examined in 

 some detail. In the first place an abundance of moisture 

 in the soil is always associated with a low percentage 

 of dhurrin, and sickly plants growing in water-logged soils 

 contain only a minute quantity. The contrary is aiso 

 probably true, nam- ly that a defic ency of moisture in the 

 soil, or a dry season conduces to excessive production of the 

 glucoside. Secondly, it is not necessarily true that the rate 

 of growth has a correlation to the poison-producing power in 

 the plant. In the case of strong and weak plants growint; side 

 by side in the same field, the weak plants do not always yield 

 the greater amount of hydrocyanic acid. Thirdly, there is a 

 far greater amount of nitrogen accumulated in the leaves than 

 in the stalk. The appearance of this greater quantity of 

 nitrogenous substances in the parts where the greatest quantity 

 of hydrocyanic acid occurs, is an indication that the production 

 of the glucosides is in some way correlated with the produc- 

 tion of the nitrogenous matter. Waterlogging presents an 

 unfavourable condition for nitrogen assimilation, as it 

 prevents bacterial activity and stops nitrification. In warm, 

 dry weather, before the rains have actually fully set in, the 

 seat of nitrification is much nearer the surface, and presents 

 a more favourable condition for nitrogen assimilation by 

 the young plants whose roots at the time do not penetrate 

 very deep. With the c nning in of the rains the bacterial 

 activity moves downwards, when the glucoside formed is 

 rapidly utilized to furnish higher and more complex com- 

 pound.", so that there is less and less hydrocyiuic acid 

 obtained as the plant grows up. In years of scanty rainfall, 

 when the vital activities of the plant are retarded on account 

 of lack of moisture, the utilization of the cyanogenetic com- 

 pounds probably takes place much more slowly, and the 

 plant contains a quantity of the poison which it cannot 

 at once utilize for higher compounds. 



It would appear, therefore, that the weather is mainly 

 responsible for the development of the poisonous principles in 

 Aadropogon. The soil is only of minor importance, and is 

 accountable for the condition only so far .as it can supply 

 nitrogenous food materials to the plant. The soil, therefore, 

 though it may help in the production of the glucoside, is only 

 a minor factor, and the weather, notably rainfall, is the factor 

 of most importance. 



DEPARTMENT NEWS. 



Sir Francis Watts K.C.M.G., Imperial Coimais- 

 sioner of Agriculture for the West Indies, intends to 

 leave Barbados for England about the i-nd of the 

 month, on duty. 



