36 



|)lain, and it is possible that some varieties, as Mr. Thomson suggests 

 would succeed better in the hill?. It is hoped, so soon as stock of these 

 ■varieties has been established, to conduct careful experiments as to the Ag- 

 ricultural yield and the content of Starch. It will also be of interest ta 

 note whether acclimatisation will cause an increase in the amount of prua- 

 fiic acid obtainable from the tubers. 



A comparative test of these cassavas against our Creole stook of bitter 

 and sweet varieties is eminently desirable. Should these Colombian varie- 

 ties maintain their promising character, their introduction from the inte- 

 rior of Colombia by Mr. Thomson to the West Indies and the Indian Em- 

 pire must be regarded as a signal service. 



The seventeen varieties were delivered on the afternoon of November 

 28th, in a perfectly fresh state, and were immediately prepared and 

 sampled for analysis. Determinations of moisture, total solids, starch and 

 hydrocyanic acid were made. The latter was determined by Carmody's ♦ 

 method of soaking slices in water. The hydrocyanic acid was estimated 

 after 24 hours soaking and again after 48 hours in a fresh quantity of 

 water. The amounts so obtained were remarkably low, far below Car- 

 mody's minimum for sweet cassava grown in Trinadad. I anticipate as 

 possible that these Colombian varieties may develop a higher prussic 

 acid content when acclimatised to Jamaica. In their present state these 

 cassavas are practically non-poisonous, and the analytical data fully sup- 

 port the reputation for harmlessness which Mr. Thomson ascribes to 

 them as grown in Colombia. 



Carmody's average for bitter cassava grown in Trinadad is 0.022 per 

 cent, and for sweet cassava 0-010 per cent, and of the latter, peeled for use 

 as a food product, 0-007 per cent, uf hydrocyanic acid. The average of these 

 seventeen Colombian varieties is only 0-001 7 or only ^of that in Trinadad 

 sweet cassava. Further experiments are in hand to test the distribution of the 

 poisonous hydrocyanic acid as between the inner and the outer portions of 

 the tubers. Carmody (loc. cit.) states that his experiments indicate that an 

 analytical difference can be drawn between "sweet" and "bitter" cassava by 

 the factthat in the former most of the hydrocyanic acid is derived from the 

 external portion, while in the latter the poison is uniformly distributed. 

 — As regards starch yield the variety Governor Hemming leads with 36.5 

 per cent., a very hi^h content closely followed by Cabesa Dura, Negrita, 

 Eelada andPaloma. 



The three Pacho Varieties (2, 3 & 4) are the lowest in starch content with 

 '22.3 to 19.3 per cent, Mr. Thomson states that these varieties should do 

 well at a high elevation There is thus a variation of 90 per cent, iu the 

 starch content of these seventeen varieties. Given a high percentage of 

 starch and large agricultural productivity, the yield of starch in Jamaica 

 should be considerable. 



The variation of moisture from 54 to 72 per cent, is also worthy of note, 

 as also the variation of 3.5 to 19 per cent, in solids other than starch. 



It is hoped on a future occasion to supply data in which the composition 

 of the tubers shall be returnable as an agricultural yield per acre of food 

 or of commercial starch and glucose. 



Appended are the analyses in which I was assisted by Messrs. Hammond 

 and Wortley. 



An interesting Memorandum from Mr. Thomson follows : 



In view of the importance of cassava both as a food product and a source 

 ,of starch, arrangements have been made for a systematic trial of various 



* Auaual Report Government Analyst Triaidid, 1931. 



