1^^ Dr. Schunck on the Formation of Indigo-blue. 



standing was changed into a crystalline mass. The solution in 

 muriatic acid left on evaporation a crystalline residue. It was 

 easily soluble in caustic soda, and the solution evolved no am- 

 monia on being boiled, but when the dry substance was heated 

 with soda-lime, it gave off a strong smell of ammonia accom- 

 panied by a peculiar penetrating odour. The watery solution 

 was neutral to test-papei', and had no perceptible taste. When 

 mixed witli freshly precipitated oxide of copper and boiled, the 

 watery solution became sky-blue; the filtered liquid gave no 

 precipitate with caustic soda, and on being evaporated left a 

 residue consisting of bright blue crystals. The watery solution 

 gave no precipitate with nitrate of silver, but on the addition of 

 a little ammonia, there was deposited almost immediately a quan- 

 tity of small crystalline scales, which blackened slightly on expo- 

 sure to the light, and were not easily soluble in an excess of 

 ammonia. The watery solution gave no precipitate with acetate 

 of lead, and even on adding ammonia there was only a slight 

 precipitate ; but on allowing the ammoniacal liquid to stand for 

 some hours, there was formed a crystalline mass of a pearly lustre, 

 consisting of needles arranged in star-shaped masses. 



The analysis of the substance gave the following results : — 



0-34!30 grm., dried at 100°C. and burnt with chromate of lead, 

 gave 0'68.20 grm. carbonic acid and 0'3125 water. 



0-3550 grm. gave 0-4125 grm. chloride of platinum and 

 ammonium. 



The composition in 100 parts agrees tolerably well with that 

 required by the formula of leucine, C'^H^^NO'*, as will be seen 

 from the following comparison of the calculated composition with 

 that found by experiment : — 



Eqs. Calculated. Found. 



Carbon . . 

 Hydrogen. . 

 Nitrogen . . 

 Oxygen . . 



However strange the fact of leucine, a substance hitherto sup- 

 posed to be a product of decomposition peculiar to animal mat- 

 ters, being obtained from the decomposition of a vegetable sub- 

 stance may have ajipearcd at a former period, it will no longer 

 excite surprise at the present time, when so many different 

 bodies have been found to be common to both classes of organ- 

 isms. It is a fact, however^ which seems to imply some con- 

 nexion, hitherto unsuspected, between leucine and indigo-blue. 



The brown syrup precipitated together with leucine by the 

 addition of tether to the alcoholic solution, consisted chiefly of 



