694 



rated solution of putassiain-oxalate, and 230 ccm of a saturated 

 solution 0Ï oxalic acid, was heated on the waterbatii under continuous 

 stirring, till all the carbonate had entered into solution. The liquid thus 

 obtained was cooled to 40° C, and then 30o;rammes of fine!}' pulverised 

 lead-peroxide-. PbO^ were added. After some time 50 ccm of a 50 7o 

 solution of acetic acid were slowly added to the rigorously cooled 

 solution under continuous stirring. Then the liquid was tiltered 

 and precipitated hy 400 ccm of 97 "„ alcohol; the green precipitate 

 was sucked off, and several times washed with absolute alcohol. 

 In this way 80 grammes of the dark green potassium-cohalti-oxalate 

 were readily collected. 



^ 2. The silver-, and the haj^iiim-ssiUs being both only slightly 

 soluble, we used the potassiiiin-s-dh itself for the preparation of the 

 corresponding strj/c/uwie-compound, thus avoiding the troublesome 

 use of large volumes of solution ; this is of advantage, because also 

 at lower temperatures the solutions are partially decomposed under 

 development of carbondioxide. The stri^chniiie-HRh ^) is for the greater 

 part precipitated, if the calculated amount of strychnine-sulpliate is 

 added to the solution of the potassium-sah, and only so much cold 

 water is consequently added as to dissolve the precipitate formed. 

 All these experiments were executed in a dark room, where the 

 solution is left standing in an open vessel for several weeks, at a 

 temperature of about 16° C; the fractions successively deposed from 

 the mother-liquor are collected separately. 



The crystals obtained are treated, in the same way as described 

 on former occasions, with ein excess of potassium-iodide, the strychnine- 

 iodide is sucked off, and the filtrate precipitated by means of 97 " „ 

 alcohol. The salt obtained is purified by repeated crystallisations 

 from a small quantity of water. 



The first fractions of the stri/chnine-s-dU in this way gave crystals 

 of the laerogy ratory antipode, containing 1 molecule of water of 

 crystallisation. The determination of the water-content cannot be 

 made at 120° C, because of the decoraposibility of the substance; 

 it was therefore made by passing a current of dry air at 20° C 

 over the finely powdered substance during a very long time, and 

 a loss of weight corresponding to 0,8 molecules of water was 

 finally observed. 



With respect to the light-absorption by the dark green solutions, 



') Originally the separation of the racemic salt was tried by the aid of cincho- 

 nine, but without success. Afterwards we repeated these experiments under some- 

 what varied conditions, but they gave no positive results either. 



