1903.] 



On the Nucleoproteids of the Pancreas, etc. 



389 



Although unable to separate the reducing substance in a state of 

 purity, he succeeded in preparing an Osazone of constant melting- 

 point and the characters of which agree with those of the osazone of a 

 pentose, an observation which absolutely coincides with the researches 

 of Kossel and Bang, which establish the presence of a carbohydrate 

 nucleus in the nucleinic acids and the formation of pentoses when they 

 are subjected to the hydrolytic action of dilute mineral acids and heat. 

 Further, Hammarsten showed that when his nuclein was decomposed 

 by heating with a 3 per cent, solution of sulphuric acid on the water 

 bath, a crystalline sediment often separated which, after being purified,, 

 was analysed and shown to consist of guanine sulphate. Later, at 

 Hammarsten's instigation, Ivar Bang, continuing the investigation,, 

 prepared from Hammarsten's nuclein, the nucleinic acid to which he 

 ascribed the name of Guanylic Acid. 



Part 2. — Experimental. 



On the Nucleoproteid of the Pancreas and on Certain Characters of the 

 IXucleins which are associated with, or derived from, if. 



A. The Nucleoproteid. 



Method of Preparation. 



The finely divided pancreas of the pig was treated successively with 

 50 per cent, alcohol, 75 per cent, alcohol, and 95 per cent, alcohol, and 

 finally subjected to the action of absolute alcohol and ether, with the 

 object of dehydrating it. The material thus obtained was extracted 

 with successive portions of a 5 per cent, solution of ammonium acetate, 

 the united extracts were filtered, and the perfectly clear fluid was 

 poured into four times its volume of weak alcohol. The precipitate thus 

 formed was washed by decantation with a large amount of dilute 

 alcohol, and finally dried w T ith absolute alcohol and ether. The object 

 of this series of procedures was to remove the colouring matter of the 

 gland, which is somewhat soluble in dilute alcohol, more so in an 

 alcoholic solution of ammonium acetate, but soluble to a very slight 

 extent in an aqueous solution of ammonium acetate. These manipula- 

 tions also remove a large amount of inorganic salts, and render the 

 coagulable albuminous substances insoluble. 



A 2 per cent, aqueous solution of this raw material had only a pale 

 yellow colour, and it was found that it could easily be examined in a 

 tube measuring 220 mm. with the polarimeter, monochromatic sodium 

 light being employed. The polarimeter was a " Halbschatten-Polari- 

 meter " made by Schmidt and Haensch of Berlin. The result of the 

 examination was to show that the solution contained a dextrorotatory substance. 

 The solution, moreover, failed to give any indication of the presence of a 

 reducing substance, even by prolonged boiling with Fehlinfs solution, and 



