134 On ih« Conversion of Animal Mailer into 



the water from time to time; then saturated with chalk and 

 evaporated, and it yielded an extract not sensibly saccharine, but 

 which had such a decided taste of osmazome, that it appeared 

 to me fit to be used in preparing soup. This extract rubbed with 

 potash disengaged ammonia. In the fire it swelled and burnt, 

 leaving a coal easy to incinerate. The solution of the extract did 

 not putrefy in a gentle and long continued heat. Some of the 

 extract was boiled at several intervals with alcohol of 34° (Baum^), 

 the different portions of spirit were mixed together, and deposited, 

 on cooling, about a gramme of a peculiar white matter, which 

 for the present I shall term leucine. 



Of Leucine. 



Leucine when dry is white and pulverulent, but still retains a 

 little animal matter, precipitable by adding tannin with precau- 

 tion to the solution. After some hours standing, I filtered the 

 liquor, which passed colourless. I then evaporated it till a 

 pellicle formed on the surface ; under which, after twenty-four 

 hours standing, one could distinguish small mamillated crystals 

 somewhat crisp in the mouth, and of a dead white, lining the 

 bottom of the dish. If, on the other hand, the solution of leucine 

 in tepid water be left to spontaneous evaporation, there form on 

 the surface a multitude of small detached, flattened, circular 

 crystals, exactly resembling button-moulds, with an inverted edge 

 on their circumference, and a depression in their centre. Leu- 

 cine has an agreeable taste of gravy or broth. It is lighter than 

 water, swimming on its surface. When heated in a small glass 

 retort it melts, but at a much higher temperature than boiling 

 water gives out a smell of boiled meat, and partly sublimes in 

 small granular opake-white crystals: the remainder, which is 

 liquid, contains empyreumatic oil^ and renders blue the reddened 

 colour of litmus. 



The solution of this sublimate in water is not troubled by sub- 

 acetite of lead, nor any other of the usual metallic tests, except 

 nitrate of mercury, which entirely separates it from its solvent, 

 in the form of a white flocculent precipitate, the supernatant 

 liquid assuming a rose-colour. 



Leucine dissolves readily in nitric acid. If this solution be 

 heated to expel the greater part of the acid, a very slight effer- 

 vescence is perceptible, but no production of red nitrous vapour; 

 and the remaining solution, after gentle evaporation, congeals 

 into a crystalline mass, which, after pressure between filtering 

 paper and re-solution in water, crystallises into thin, divergent, 

 colourless needles. This forms a peculiar acid, analogous to the 

 nitro-saccharine above described. 



This nilro-leucic acid forms peculiar salts with the several 



bates. 



