June 1908.] 



531 



Edible Products. 



species of Phaseolus which sometimes 

 exhibits marked poisonous properties. 

 It is desirable that great care should 

 be taken iu selecting for cultivation the 

 best variety of Lima beans, The large 

 oval white seeded kinds, with at most 

 a brown or black mark close to the 

 hilum, are preferable to those with 

 flattened reniform seeds having blotcUes 

 of red or veinings of black." 



On this point it is of interest to note 

 thatCordemoy has stated (" Flore de l'i le 

 de la Reunion," 1865, p. 389) that in the 

 wild state the beans of Phaseolus lunatus 

 are purple and very poisonous ; that on 

 cultivation the colour of the seeds be- 

 comes modified to a yellowish tint with 

 stripes or violet splotches, and that in 

 this state the beans are rarely poisonous ; 

 and lastly that, after prolonged culti- 

 vation, large white beans are produced 

 which are harmless. This statement, 

 taken in conjunction with the facts 

 recorded above, seemed to indicate that 

 by cultivation of the plant the beans 

 become white and then no longer pro- 

 duce the glucoside capable of yielding 

 prussic acid. 



After carefully reviewing the facts in 

 consultation with the Director of the 

 Imperial Institute, the Board of Agricul- 

 ture came to the conclusion that it was 

 desirable at this stage to warn con- 

 sumers against the use of red and dark 

 coloured beans of Phaseolus lunatus. 

 (Journal, December, 1902, p. 373). 



In 1905 interest in the matter of the 

 production of prussic acid by the beans 

 of Phaseolus lunatus was reawakened 

 by the importation into the United 

 Kingdom of large quantities ot beans 

 from Java, to the use of which, for 

 feeding cattle, numerous cases of poison- 

 ing were traced, especially in Scotland.* 



Samples of these "Java beans" were 

 received at the Imperial Institute from 

 various firms. They closely resembled the 

 beans of Phaseolus lunatus, as received 

 from Mauritius, and on examination 

 proved, like these, to yield compara- 

 tively large quantities of prussic acid^ 



These "Java beans" were imported, 

 not only into the United Kingdom, but 

 also into Holland, Germany and France, 

 and in all three countries similar poison- 

 ing cases occurred. 



At this period a systematic investiga- 

 tion of the beans of Phaseolus lunatus, 

 as produced in different localities, was 

 undertaken by Professor Guignard 

 ("Comptes Rendus," 1906, CXLVII, 515), 

 and an examination of Java beans was 

 made by M. Kohn-Abrest (ibid., p. 586). 



'Journal, March, 1906, Vol. XII, p. 742, and 

 April, 1906, Vol. XIII, p. 52. 



*7 



Both these investigators confirmed the 

 observations made at the Imperial Instit- 

 ute that the Java beaus yielded com- 

 paratively lar^e quantities of hydro- 

 cyanic acid. Professor Guignard also 

 found that red Rangoon beans yielded 

 small amounts of prussic acid, but he 

 stated that the white cultivated beans 

 of PJianeolus lunatus, such as those pro- 

 duced in Madagascar, Rangoon, South- 

 ern France, &c also yielded prussic 

 acid, though in most cases only in mere 

 traces. 



Messrs. Tatlock and Thomson ex- 

 amined a number of commercial samples 

 of Java, Rangoon and haricot beans, and 

 their results, which also indicate that 

 some samples of the white beans of 

 Phaseolus lunatus yield prussic acid, are 

 given in the Analyst for August, 1906. 



In March, 1907, Mr. Hendrick, chemist 

 to the Highland and Agricultural Society 

 of Scotland, sent to the Imperial Instit- 

 ute a sample of white Rangoon beans, 

 which he had found on examination 

 yielded '01(5 per cent, of prussic acid. 



In May, 1907, the Board of Agriculture 

 called the attention of the Director of 

 the Imperial Institute to the fact that 

 white Rangoon beans had been found 

 in some instauces to yield prussic acid, 

 and as it seemed desirable that the 

 matter should be further investigated, a 

 request was made to the Board of Agri- 

 culture for samples of Rangoon beaus as 

 sold throughout the United Kingdom 

 for feeding purposes. A series of such 

 samples, collected mainly in Scotland 

 and the North of England by one of the 

 Board's Inspectors, was received last 

 July. 



The Imperial Institute also obtained 

 a number of samples of white Burma 

 beans and other white beans of Phaseo- 

 lus lunatus from firms in London and 

 Paris, so that the inquiry could be made 

 as general as possible. 



The results of the examination of 

 these samples are given in the following 

 table :— 



Samples Received from the Board 

 op Agriculture. 



Prussic Acid. 

 Per cent, 



Red Rangoon beans, obtain- 

 ed at Leith ... ... 0-021 



White Rangoon beans, ob- 

 tained at Leith Traces, too small 



to estimate 



Hand-picked white Rangoon 

 beaus, obtained in New- 

 castle... ... ... 0-020 



White Rangoon beans, ob- 

 tained in Newcastle ... 0'018 



