70 ON THE VEGETABLE CHEESE, NATTO. 



precipitate was mixed with mercuric nitrate with the gradual 

 addition of small quantities of soda as long as a precipitate was 

 formed. This precipitate, after being washed well on a filter, was 

 decomposed by sulphuretted hydrogen, and the filtrate evaporat- 

 ed on the water bath, ammonia being, from time to time, added 

 to keep the solution neutral. In the concentrated liquid were 

 formed after some time white crystalline masses composed of 

 radiating needles of the forms characteristic of tyrosin. They 

 were easily soluble in dilute ammonia and in hydrochloric acid, 

 slightly soluble in cold, and easily in hot, water. They were 

 purified by repeated recrystallisation, and then yielded the reac- 

 tion of Piria, Wurstcr and Hofmann for tyrosin. The determina- 

 tion of nitrogen by KjcldahVs method yielded 7,98%, while the 

 theory requires 7,75 %. Also the copper compound was ob- 

 tained by boiling the solution with copper hydrate and filtering 

 while hot. The total quantity obtained amounted to 3.212 

 grm. The mother liquor from which the tyrosin was separated 

 was farther concentrated and divided into two parts (a) and (b). 

 The part (a) was precipitated with phosphotungstic acid after the 

 addition of a little sulphuric acid (c) and the filtrate mixed with 

 caustic baryta to separate the sulphuric acid and phosphotung- 

 stic acid. After the removal of the excess of baryta by a current 

 of carbon dioxide, the filtrate was evaporated. Numerous 

 spherocrystals were obtained with the behavior of leucin mixed 

 with the crystals of ammonium nitrate. To remove the latter, 

 a little baryta was added and by evaporation the ammonia was 

 expelled. When the residue was treated with alcohol, barium 

 nitrate remained behind while the alcoholic solution on evapora- 

 tion yielded crystals of leucin which were converted into the 

 characteristic copper compound which yielded on analysis 

 19.76% copper, while the formula (C 6 H* 2 N0 2 ) 2 Cu requires 19,5%. 



The phosphotungstic precipitate (c) was first washed with 

 cold water containing some sulphuric acid and then decomposed 

 in the usual way with caustic baryta and the filtrate after remo- 

 val of the excess of baryta evaporated, whereby a syrupy liquid 

 was obtained. I searched here for lysin, lysatinin (both discovered 

 by Drechscl) and arginin (discovered by Schulze), which are the 

 decomposition products of the proteids of the germinating lupines, 

 but all my efforts were in vain. The syrup gave, however, all 



