TRANSACTIONS OP THE SECTIONS. 55 



ing under diabetes for some weeks, was the patient from whom the urine was ob- 

 tained. Its specific gravity was 1035 ; 300 grains of the fluid yielded 25'9 grains of 

 sugar. The urine, when evaporated, afforded a honey-like residue ; but upon care- 

 fully evaporating a portion, and pouring off gradually the fluid part, rhomboidal 

 colourless crystals were procured. These possessed a saline taste, and upon being 

 analysed, yielded — 



Volatile matter 8-04 ... 80*4 



Common salt 1-96 ... 19-6 



10-00 100 



They were, therefore, obviously the well-known compound of sugar and common 

 salt. According to Peligot, this compound contains from six to seven per cent, of 

 water ; the above analysis would therefore give — 



Sugar 73-4 



Common salt 19"6 



Water 7 



100-0 

 The crystals were not quite pure, which accounts for the deficiency of common salt 

 compared with the results usually given. 



The author has since been enabled to obtain very regular crystals, and to procure 

 any quantity of saccharine crystals from diabetic urine, by adding a small portion of 

 common salt during the evaporation of the urine. He found that very regular cry- 

 stals obtained in the Glasgow laboratory, and which were supposed to be pure sugar, 

 contained common salt ; the urine from which it was procured possessing an extra 

 quantity of common salt. He has also been informed by Mr. M'Gregor of Glasgow, 

 that the crystals of saccharine matter obtained by him in his experiments, were found, 

 on being tested, to contain common salt. The facility or difficulty of obtaining cry- 

 stallized diabetic sugar would appear to depend on the quantity of common salt ex- 

 isting in the fluid from which the crystallization is made. 



These observations would therefore seem to call in question the accuracy of the 

 conclusion, that diabetic sugar is capable of crystallizing in a regular form, or of as- 

 suming a superior crystalline structure to that of grape sugar. 



On the Radical of the Kakodyle Series. By Prof. Bunsen. 



The method recommended as the easiest of procuring kakodyle in a pure state is the 

 following: — Chloride of kakodyle, carefully freed from the oxide by treatment with 

 strong muriatic acid, is allowed to stand some time over chloride of calcium and 

 quick-Ume to remove the water and all excess of acid. It is then introduced into a 

 distillatory apparatus, carefully filled with carbonic acid, and containing some slips 

 of clean sheet-zinc. Any of the metals which decompose water will answer, but 

 zinc is best. It is probable that hydrogen or carbon would produce a similar de- 

 composition with suitable modifications of the apparatus. The vessel is then her- 

 metically sealed, and the mixture of zinc with the chloride is exposed in a water-bath 

 to a temperature of 212° Fahr. for some hours. When the decomposition is com- 

 plete, a white saline mass is formed, which melts into an oily liquid between 240° 

 and 248° Fahr. While the apparatus is still hot, the point of the tube leading into 

 the condenser is dipped below the surface of boiled distilled water ; as the appa- 

 ratus cools the water rises into it. The tube is hermetically sealed ; the water dis- 

 solves chloride of zinc, leaving the excess of zinc and the kakodyle, which falls as an 

 oily liquid to the bottom. This is rectified twice or three times in vessels filled with 

 carbonic acid as before, the water being afterwards removed by chloride of calcium 

 in the usual way. Thus obtained it is a colourless liquid, transparent, and of a high 

 refractive power, in appearance and odour much resembling the oxide of kakodyle ; 

 it ignites instantly on being brought in contact with air, giving oft' water and car- 

 bonic and arsenious acids. If air be gradually admitted, thick white clouds are 

 evolved, and oxide of kakodyle and kakodylic acid are formed. If the supply of 

 oxygen be insufficient for complete combustion, erythrarsin is deposited, mixed with 

 a black fuetid layer of arsenic. In chlorine kakodyle burns with a brighter flame, 

 depositing charcoal. Digested with zinc and muriatic acid, erythrarsin and a variety 



