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Phaseolus Lunatus Beans. 



[march, 



small quantities of the poisonous beans of Psophocarpus tetra- 

 gonolobus, and that their production of prussic acid may be 

 due to such inclusions. The only extraneous beans noticed in 

 samples, both of Rangoon and Java beans examined at the 

 Imperial Institute, have been those of Dolichos lablab, which 

 Dr. Leather has shown also yield small quantities of prussic -acid. 

 None of the investigators who have worked on Rangoon beans 

 have recorded the occurrence among them of Psophocarpus 

 tetragonolobus beans, so that there is no evidence to support 

 the Consul's suggestion, whilst there is plenty of evidence 

 that the Rangoon beans themselves actually yield prussic 

 acid. 



Although both red and white Burma beans have been im- 

 ported in large quantities into the United Kingdom, and used 

 for feeding cattle during the last few years, no cases of poison- 

 ing have so far been traced to them, but it is obvious that if 

 the amount of prussic acid furnished by different consignments 

 of these beans may vary over as wide a range as is shown by 

 the figures quoted above, the use of these beans for feeding 

 cattle may be attended with some danger. 



There is nothing on record to show what ill effects — if any — 

 are produced by the long-continued use of feeding materials 

 capable of producing small quantities of prussic acid, but the 

 following facts are of some interest in this connection. It was 

 shown by Jorissen and Hairs as long ago as 1888 that ground 

 linseed when placed in contact with water yields prussic acid, 

 and these authors found that this was due to the interaction 

 of a glucoside and ferment. Recently, in conjunction with 

 Dr Auld, we have re-examined the glucoside and ferment 

 of linseed and found that they are identical with the cyano- 

 genetic glucoside and ferment of the beans of Phaseolus lunatus. 

 (Proc. Roy. Soc, 1906, B. LXXVIII, 152). Since in the mere 

 expression of oil from linseed the glucoside is not destroyed, 

 it became of interest to ascertain how much prussic acid is 

 furnished by the linseed cake commonly used as a feeding stuff 

 for cattle in this country. Samples of linseed cake were there- 

 fore obtained from two of the principal makers of this product 

 in the United Kingdom. The samples of cake were both of the 

 highest quality, and the linseed from which they were made 

 was guaranteed by the firms to contain a minimum of 



