THE ANTIBERIBERI VITAMINE 167 



great stability. It is possible, on the one hand, that we may need 

 new chemical methods in order to discover their chemical nature; 

 on the other hand, it is not unlikely that our older methods, which 

 have been of such use to us in the identification and isolation of so 

 many naturally occurring products, may lead us to the desired goal. 

 We have already pointed out the status of this question, up to 

 1911, in the historical part. We stated that till then, the investiga- 

 tors in this field were in doubt as to whether the factor curing beriberi 

 was really a chemical substance. We have shown, together with 

 Cooper (I.e. 68) that when pressed yeast is hydrolyzed by boiling 

 vigorously with 20 per cent sulphuric acid for 24 hours, a id then the 

 sulphuric acid completely removed with baryta, the evaporated 

 filtrate still exhibited a very marked curative action. This stability 

 in the presence of acid makes it appear that the substance in question 

 is an organic base, which would distinguish itself by the known 

 chemical characteristics of this class of substances. Based upon this 

 assumption, we (463) undertook a systematic investigation of rice 

 polishings. 



CHEMICAL INVESTIGATION OF RICE POLISHINGS 



Since no chemical reaction was known for the demonstration of 

 this vitamine, every one of the investigated fractions was tested on 

 beriberi pigeons. The stage at which vitamine was administered 

 (mostly given per os in the beginning) was the appearance of con- 

 tractions of the neck, wings and legs. Left to themselves, the 

 pigeons died in about 12 hours from the onset of the above symptoms. 



A series of preliminary experiments were made in order to secure 

 an active solution of the simplest possible composition. This was 

 obtained by shaking rice polishings, which consist chiefly of cellulose, 

 phytin and fat, with alcohol saturated up to a certain point with 

 gaseous hydrochloric acid. This procedure possessed the advantage 

 that the solution was completely freed of alcohol insoluble material. 

 The alcoholic solution was then concentrated in vacuum, yielding a 

 fatty residue. This residue was melted on the water bath, extracted 

 with hot water, and the layers separated in a separatory funnel 

 while still hot.. The watery extract, which was very active, was 

 treated with sulphuric acid till a 5 per cent solution was obtained, 

 and then completely precipitated with a 50 per cent phosphotungstic 

 acid solution. The precipitate was decomposed with baryta and the 



