D. CHEMISTRY AND METALLURGY. 107 



was the occurrence of a large percentage of oil in the clean 

 salmon, and a deficiency in that of the poorer qualities. As 

 a mean of the examinations made by Professor Christison, 

 he states that in clean salmon there are 18.53 per cent, of oil, 

 19.70 per cent, nitrogenous matter, 0.88 per cent, saline mat- 

 ter, and of water 60.89 per cent.; while in foul salmon the 

 amount of oil was only 1.25 per cent., and of water 80.88 per 

 cent., the saline and nitrogenous matter not being materially 

 different, although the latter was somewhat diminished. 

 2 A, April 13, 1872,257. 



TESTING ANIMAL FLUIDS. 



According to Mr. J. A. Wanklyn, the differential action of 

 potassic hydrate and potassium permanganate may serve as 

 a method to distinguish between various animal fluids. When 

 these are evaporated down with excess of potassa solution, 

 and then maintained for some time at 150, a certain propor- 

 tion of ammonia is evolved ; and if the residue be now boiled 

 with an alkaline solution of potassium permanganate, a fur- 

 ther definite quantity of ammonia is given off, the relative 

 amount of ammonia evolved by these two additions being 

 constant for the same animal fluid. The author has exam- 

 ined by this method urine, milk, blood, white of egg, and gel- 

 atine, the latter of which gives but a mere trace of ammonia 

 by treatment with caustic potash. It would be possible by 

 this process to distinguish between a spot of milk and one 

 of white of egg on a cambric handkerchief. 1 A, June 14, 

 1872,284. 



PURPUROPIIYL, A DERIVATIVE OF CI1L0R0PHYL. 



If we boil chlorophyl with potash lye for a quarter of an 

 hour we shall have a mixture of a green color, which may 

 be filtered, and hydrochloric acid added. As soon as the 

 potash is neutralized a precipitate is produced ; and on add- 

 ing more acid the liquid becomes of a bright grass-green col- 

 or ; and Avhen again neutralized with carbonate of lime a 

 green precipitate is formed, constituting a new substance, 

 which has been called purpurophyl. This, when washed with 

 water and covered with alcohol, assumes a fine purple tint, 

 and is turned green by ammonia. 3 A, June 29, 1872, 560. 



