Vol. VII. Xo. 154. 



THE AGRICULTURAL NEWS. 



87 



HYDROCYANIC ACID CONTENT OF 

 CASSAVA. 

 The question of the danger of poisoning arising 

 from the consumption of imperfectly cooked cassava has 

 formed the subject of several notes and articles in the 

 Agricaltural News (Vols. I, p. .5; II, p. 102 : and III, 

 p. 423), and a leaflet (Hints nvd Ivforiiuitum in 

 reijavil to Cassava 2~>oison i nr/) dealing with the subject 

 was issued some two or three years ago. 



Some investigations in connexion with the amount 

 of hydrocyanic acid .nnd starch present in ciLSs.iva have 

 recently been carried out by the Hureau of Chemistry 

 of the U.S. Department of Agriculture, and the results 

 ai-e published in Bulletin Nn. /'>^' of the Bureau. The 

 previous woi'k that has been done in I'olation to this 

 question has chiefly been undertaken in Trinidad by 

 Professor Carmody and his pre<leccssor in the office of 

 Government Analyst, and by the Hon. H. H. Cousins 

 in Jamaica. 



(."as.sava lui.s been ilivided into sv.-eet and bitter varietie,-;, 

 and although .sweet (.'as.sava.s are considered to be less poison- 

 ous than the bitter varietie.s, yet it ai)[>ear.s that the sweet or 

 bitter (.■haracter of a cas.sava is not directly connected with 

 its content of hydrocyanic acid, but is dependent upon the 

 absence or iire.sence of some bitter prjnciple. As the result 

 of his investigations, made some fi^'e year.s ago, Professor 

 Carmody rei)orted the mean percentage of hydrocyanic acid 

 in the sweet varieties examhied as OPIO, and in the bitter 

 varieties as 0022. It is usually helij that sweet varieties 

 contain only half as much iiriissic acid as those known to 

 have been fatal. 



A'ai'ieties of cassava gmwn in Colombia, and analy.sed 

 by the Covernment Analyst of Jamaica .showed a mean jier- 

 centage of only O'OOl of hj'drocyanic acid, the maximum 

 being only 0003. From this it apjiears that all the Colom- 

 bian cassavas may practically be classed as sweet. 



On the other hand, analyses of native bitter cassavas made 

 by the same officer show percentages of hydrocyanic i^cid of 

 from 0036 to 0-077. 



Professor Carmody suggests that the difference between 

 the two kinds consists in the hydrocyanic acid being distribu- 

 ted throughout in the bitter kind, wdiereas in the sweet 

 varietie.s, it exists chiefly in the cortex. 



In regard to the proportion of hydrocyanic acid present, 

 this is certainly influenced by environment, and the experi- 

 ments with cassava that have been in progress in .bunaic;i fur 

 some years past (J.(7/v'(V(/^(/Y(/ J'e»'.s-, Vol. VI, p. 261) M-ould 

 appear to indicate that when a variety — usually cultivated in 

 elevated districts —is transferred to lower levels of country, the 

 proportion of hydrocyanic acid tends to increase, ilr. Cousins 

 reports that fcjurteen varieties of cassalva., stuted to be quite 

 non-poisonous in Colombia, were testefl after a year's growth 

 in the Liguanea plains of Jamaica, and were found to cf)ntain, 

 on the average, 0'0034: per cent, of hydrocyanic acid. After 

 a further jieriod of four years' growth in the same changed 

 locality the hydrocyanic acid content rose to 0124 per cent., 

 or practically fourfold. On the other- hand, a report *'rom 

 Trinidad, dealing with this ipie.stion, notes that residents of 

 Coloml.iiii, who have imported bitter varieties from Jamaica, 

 find they have become sweet. 



The work referred to as having l)een carried out in the 

 ITnited States was conducted at lUlonii, Mi.ssi.ssippi, and at 

 Miami, Florida, in 1904 and TOO"). Cassava is a crop that 

 may be grown in any of the (Julf States, and it was felt that 

 the great feeding value of the roots, could the danger of 

 iioisonin" le eliminated, justified investigation of the 



hydrocyanic and starch contents of different varieties, and the 

 conditions which influenced variation in these constituents. 

 Thirty-nine varieties were under trial at Biloni and 

 twenty-eight at iliami. The whole of those raised at Miami 

 were originally obtained from .Jamaica, while at Biloni twelve 

 varieties from Porto Rico were grown in addition to the 

 Jamaica kinds. At Biloi^i, a common native variety, Florida 

 Sweet, was also grown. 



It is curious to noteihat none of the imported varieties 

 gave so low a i)ercentage of hydrocyanic acid as 'Florida 

 Sweet,' which contained only 0002 per cent. Pie de Perdiz and 

 Cenaguera apiiroached it= nearly, however, Avith an average 

 content of 0-003. Of the cassavas grown at Biloni, Porto Rico 

 AVhite Toi:> contained the highest proportion of hydrocyanic 

 acid, 0-030 per cent. This was closely followed by Porto 

 Rico Auntie ( Jrace, with 002.S per cent., and by the Mantera 

 and a Helada variety from Jamaica, which contained 0-026 

 and 0-022 per cent, respectively. At Miami, Florida, the 

 percentage of hydrocyanic acid was, in the great number of 

 cases, soTnewhat lower than at Biloxi. In the twenty-eight 

 .so-called sweet varieties grown at Miami, the hydrocyanic 

 acid content ranges from 0-000.5 to 016 per cent., and more 

 than half the varieties contained 002 per cent, or les.s. On 

 reference to the Biloiu results with the .same varietie.s, it is 

 seen that two-thirds of the samples contained O'OIO per cent, 

 or more of hydrocyanic acid. The Mantera cassava, for 

 example, which at Biloni showed a proportion of 026 of 

 hydrocyanic acid, contauied only an average of 0-006 at 

 Miami. Statements have in the past been made to the effect 

 that varieties of cassava growni in Florida, cease in time to 

 be poisonous, and these results certainly give some ground 

 for this theory. 



The chief portion of the hydrocyanic acid was, in the 

 case of both bitter and sweet cassava, found to exist in the 

 cortex 



From the observations made, tliere does not appear to be 

 any relationship between the starch and the hydrocyanic acid 

 content of the cassavas. 



CYCLONE IN ST. KITT'S-NEVIS. 



Mr. F. R. Shepherd, Agricultural Superintendent 

 of St. Kitt'.s-Nevis, has forwai-ded a report to the 

 Imperial Commissioner of Agriculture on the damage 

 (lone by the cyclone which passed over St. Kifct's-Nevis 

 during the night of Saturday. March 7, and the early 

 In.iurs of the following morning. 



The weather had been unsettled in St. Kitt's since 

 Friday, and throughout Saturday the wiml blew in strong 

 jiuffs from the west. 



On Saturday night Jhe wind blew violently from the 

 north-west with a falling bfirometer. By midnight the wind 

 was at its height, and in Bas.seterre the barometer reading 

 fell to 29-3. Rain fell heavily, over 4 inches being registered 

 in Basseterre, and over S inches at Molineux in the northern 

 ]iart of the i.slaud. About 3 inches of rain fell in Nevis. 



The disturbance passed quickly, however, and by 10 a.m. 

 on Sunday, tlic weather had cleared, the wijul changing to east. 



As the result of the storm, a large number of trees were 

 blown down in St. Kitt's. ,The cane crop, being very advan- 

 ced, .sustained considerable damage, being levelled with the 

 ground in some cases. Apart from the lo.ss due to broken 

 canes, the quality of the. juice will be lowered as the result of 

 the heavy rains. The cotton crop of Nevis has been all 

 reaped and ginned, so con.-.equently no damage was experienced. 



At the Botanic Station a few cedar trees were blown down 

 and sonic rithcrs damaged 



