44 



The sodium was first heated, then the gum-enzyme slowly heated 

 so that the gases would pass over the glowing sodium. This test 

 was repeated in the same manner, except that the gum-enzyme 

 was first mixed with dry potassium hydroxide. In another ex- 

 periment the substance was heated with a small quantity of con- 

 centrated sulphuric acid until a dry charred mass was obtained, 

 then mixed with metallic iron and sodium and ignited, and fin- 

 ally tested for cyanide. In another experiment a modification of 

 the Kjeldahl quantitative method was tried. The gum-enzyme 

 was heated with concentrated sulphuric acid and a little mercuric 

 oxide until a colorless solution was obtained. The solution was 

 then mixed with an excess of potassium hydroxide and distilled. 

 The distillate was passed through a tube containing a piece of 

 red litmus paper into a mixture of chloroform, alcohol and po- 

 tassium hydroxide to convert the ammonia into cyanide. The 

 litmus paper remained red throughout the distillation. All at- 

 tempts to convert the nitrogen into cyanide failed. 



Another test for nitrogen which is considered less reliable 

 than the Lassaigne test, is to convert the nitrogen into ammonia 

 by heating the substance in a tube with soda-lime or potassium 

 hydroxide. This test was applied to the gum-enzyme when the 

 red litmus paper placed over the end of the tube rapidly changed 

 to blue, but no odor of ammonia could be detected. The paper 

 was evenly colored as if produced by some gaseous substance. 

 The test was repeated with a pledget of cotton inserted in the 

 tube below the paper to prevent the possibility of potassium hy- 

 droxide being mechanically carried to the litmus paper. The re- 

 sult was the same as in the previous test. A blank test was next 

 made under exactly the same conditions, but with negative re- 

 sults. These experiments indicated the presence of a volatile 

 base. Professor Tschirch thought the odor similar to pyrrol. I, 

 therefore, repeated the test, placing in the top of the tube a pine 

 shaving moistened with hydrochloric acid. This was rapidly 

 colored red, thus strongly indicating, if not conclusively proving, 

 the presence of pyrrol, or a pyrrol derivative. This was further 

 confirmed by placing 5 grammes each of powdered potassium 

 hydroxide and gum-enzyme in a flask and distilling. The 

 vapors were passed through a condenser connected with a dry 

 flask, and this again connected with a second flask by means of 

 a tube which passed to the bottom of the flask, into a small quan- 

 tity of water. At the end of the reaction the first flask contained 



