1880.] Modifications of the Spectrum of Potassium, Sfc. 



285 



siderable quantities of the same bases and salts as those obtained from 

 kephalin and myelin were isolated, but not examined any further. 



It had been ascertained in previous operations on these mixed phos- 

 phorised and cerebrin bodies, and was now again observed, that one 

 treatment with acid was insufficient to free them entirely from bases. 

 The bodies which had been treated with acid were, therefore, treated 

 with lead acetate solution in the cold, and were allowed to stand. The 

 liquid which formed was filtered from, and pressed out of the lead- 

 compounds, and on proper treatment yielded as follows : — sodium, 

 — 1'78 grm. ; potassium, = 1*185 grm. ; calcium, = 0"08 grm. ; and 

 magnesium, 0-02 grm. The sodium was weighed as chloride ; the 

 potassium, 0856 grm., as bitartrate. and 0'32 grm. as platinic chloride: 

 the calcium as carbonate ; and the magnesium as pyrophosphate. 

 The respective preparations are herewith submitted for inspection. 



Curious facts which deserve notice are the following. When so- 

 called " protagon " was decomposed by baryta to obtain neurin, it was 

 observed that the platinic chloride salt of the base always contained, 

 potassium. When the neurin was combined with phosphomolybdic 

 acid, and carefully washed, and then again transformed into platinic 

 chloride salt, it became free from potassium. In both cases the salt 

 was crystalline, but the crystallisation was different in the two cases. 

 The crystals containing potassium were most perfectly formed indivi- 

 duals, sometimes more than half an inch in length and breadth, and 

 an eighth of an inch in thickness, while, on the other hand, the 

 crystals free from potassium were bundles of needles, of lighter aspect 

 and not admitting of angular measurement. The experience shows 

 that the platinic chloride compound of potassic chloride is dimorphous, 

 and in one of its forms is isomorphous with the platinic chloride salt 

 of neurin hydrochlorate. It is further remarkable that 'the impure 

 isomorphous mixture crystallised in well-defined individuals, while the 

 pure salt crystallised in confused masses and in bundles of needles. 

 The crystals of the perfect type, when powdered and burnt on a 

 platinum wire in an aerated gas flame before the spectroscope, produced 

 the line in red characteristic of potassium. This specimen is herewith 

 submitted for inspection, as also a specimen of the salt free from 

 potassium. 



The foregoing data may perhaps contribute to explain some of the 

 discrepancies which have been found between different specimens of 

 neurin platinic chloride, and have caused the inconvenience of a 

 number of different formulae being attributed to neurin, namely, 

 C 5 H 15 N0 2 , or C 5 H u NO, or C 5 H 14 N, or C 5 H 12 N. They may also explain 

 why neurin from "protagon" has been supposed to consist of a mix- 

 ture of two bodies, having respectively the formulae C 5 H 15 N0 2 , termed 

 oxyneurin, and C 5 H 15 NO, termed neurin. According to my own 

 numerous analyses (Reports as above, No. VIII, p. 118, et seq.), the 



