TRANSACTIONS OF THE SECTIONS. 41 



The fractions distilling at 180° and between 183° and 184° C* ga-s'e on analysis the 



following results : — 



Product boiling Product boiling Theory, 



at 180° C. between 183°-184° C. CNH, CH^O. 



C 49-78 51-70 50-71 



II 7-44 7-64 7-04 



N 20-42 19-83 



These anatyses prove that the body in question results from the direct combina- 

 tion of one molecule of aldehyde and one molecule of prussic acid, or at least of 

 equal numbers of molecules of these bodies, and that its point of ebullition is inter- 

 mediate between 180° and 184°. We have tried the above experiments on mix- 

 tures containing the two generating bodies in various proportions, but always with 

 the production of the same compound. The name we propose for this body is 

 cyannydrate of aldehyde, which is simply fomided upon its synthetical formation. 

 " Proj'crtics. — The cyanhydrate of aldehyde is a colom-less liquid, having a faint 

 odour of its generators ; it has a bitter and acrid taste ; it does not crystallize at 

 — 21° C, but becomes syrupy. It can bear the temperature of 150° for a considerable 

 time without sufi'ering' decomposition ; at 180°, however, slight dissociation com- 

 mences, and the liquid must be rapidly distilled in order to avoid the loss of a 

 considerable quantit}\ It is soluble in all proportions in water and alcohol. It 

 may be heated with water in a sealed tube to 150° without suffering- the slightest 

 decomposition, and the entire liquid can be recovered by distillation. Caustic pot- 

 ash appears to separate it into its two generators, forming cyanide of potassium 

 and resin of aldehyde. A little ammonia is also evolved, owing probably to the 

 decomposition of the cyanide of potassium. 



Gaseous ammonia is absorbed by cyanhydrate of aldehyde, with the production 

 of a base, which gives a precipitate with bichloride of platinum. Our analyses of 

 this salt have not yet enabled us to ascertain the composition of the base. 



A strong solution of hydrochloric acid acts with great violence at tlie ordinary 

 temperature of the air upon cyanhydrate of aldehyde. If, however, the cyanhj-drate 

 be introduced into a balloon surrounded by a freezing mixture, and the hydrochloric 

 acid be added gradually, the two liquids mix without any reaction taking place. 

 On removing the balloon from the freezing mixture and placing it in water at the 

 ordinaiy temperature, the reaction soon commences, and proceeds gradually till the 

 entire liquid becomes a mass of crystals. These were twice treated with absolute 

 alcohol in order to separate the chloride of ammonium which is formed. On eva- 

 porating the alcoholic solution a syrupy liquid was obtained, which was saturated 

 at 100*^ with pure oxide of zinc and tiftered. The filtered liquid gave, on cooling, 

 a mass of beautiful prismatic ci-j-stals. These were reci-j'staUized, heated in an 

 oil-bath to 150' C, and analyzed. The numbers obtained prove that the body in 

 question was the lactate of zinc, as will be seen from the following Table : — 



Experi- Theory, 



ment. C3H,Zii03. 



C 29-84 29-63 



H 4-52 4-13 



Zn 26-77 26-75, 



The following equation explains the formation of this acid : — 

 CJI.O, HCN-|-HCH-2(I1,0) = C3H„0 -|-NH^Ch 



The insolubility of this salt in alcohol, its non-decomposition at ]50°, and its crys- 

 talline form, suttiiiently prove that the acid combined with the zinc was the lactic 

 acid of fermentation, and not the sarcolactic. 



The behaviour of cj-anhjalrine of aldehyde towards hydrochloric acid and caustic 

 potash, proves that it is isomeric and not identical with the cyanhydrine of glycol 

 discovered by VVisliccniuB. 



We have endeavoured to obtain the vapour-density of this body by Dumas's 

 method, but without success. On heating the balloon containing om- body to. 

 210° in an oil-bath, we observed, on removing it from the bath, that the aldehyde 

 had been converted into a resin. On deducting its weight from the weight of the 

 balloon, the density of the vapour approached very near that of prussic acid. It 

 appears to us, however, to be sufficiently proved that this compound contains only 



