112 



Mr. E. Schunck on the Colouring and [Eecess^ 



boiling water in snow-white masses consisting of star-shaped groups of 

 needles. It gave, on being tried by Piria's method for discovering tyro- 

 sine, a very decided reaction. Its watery solution also gave, with nitrate 

 of m.ercury, the reaction peculiar to tyrosine. 



Among my collection of products from urine, there is one also belonging 

 to this period ; but by what means it was procured I cannot state, as I 

 can find no memoranda relating to it among my notes. All that I can say 

 regarding its preparation is, that it was obtained, like the other, from the 

 lead precipitate with ammonia, and I think by a similar process. It is, 

 however, totally different in its properties. It consists of regular, colour- 

 less crystals, and has a sweet taste. It dissolves in boiling water, but is 

 not easily soluble in cold water. Its watery solution, on the addition of a 

 salt of copper and an excess of caustic soda, turns blue ; but no suboxide 

 of copper is deposited on boiling the liquid. From its giving, when treated 

 in the manner described by Scherer, with nitric acid, then with chloride of 

 calcium and ammonia, the pink colour characteristic of inosite, I conclude 

 that it consists of that peculiar species of sugar. 



It is well known that both tyrosine and inosite are found in the urine in 

 disease ; and as the urine employed in my experiments was secreted by a 

 great number of individuals, it seemed not improbable that among those 

 individuals there might be some whose urine contained those bodies as the 

 result of some morbid condition. In this case it would be the precipitates 

 with basic acetate of lead and with ammonia in which these substances 

 would be found, as they are neither of them precipitated by neutral acetate 

 of lead. It is possible, however, that their occurrence may be due to some 

 peculiar decomposition undergone by the extractive matters. I shall return 

 to this point when I come to describe the properties of the latter. 



F(18G0). 



The investigation had now reached a point at which, in my opinion, no 

 advantage was to be derived from attempting to devise new methods of 

 preparing the bodies under examination for analysis. I preferred going 

 over the ground again, employing the same methods as before, and obtain- 

 ing, if possible, some confirm.ation of the previous results. 



The series of experiments now to be described consists of a renewed ex- 

 amination of the three lead precipitates in which the urinary extractive 

 matters are contained — that produced in urine with neutral acetate of lead, 

 that with basic acetate of lead in the liquid filtered from the first, and that 

 with ammonia in the liquid filtered from the second precipitate. 



The precipitate with acetate of lead was treated in the manner described 

 in giving an account of the experiments of Series B. After being washed 

 it was decomposed with sulphuric acid ; the excess of the latter was removed 

 from the filtered liquid by means of caustic baryta, and the phosphoric 

 acid was precipitated by adding milk of lime. The filtered liquid having 

 been mixed with an excess of acetic acid, acetate of lead and ammonia were 



