Thialdine and Selenaldine. 471 



esting products. The study of these substances promises to 

 become highly important for the theory of the formation of 

 organic bases, in which the action of ammonia is frequently 

 very prominent, and it may be expected that a close investi- 

 gation of the production of organic substances containing 

 sulphur will throw some light upon their genei'ation in the 

 organism of the plant. 



The preparation of thialdine is very simple. One part of 

 aldehydite of ammonia free from tether and alcohol is dis- 

 solved in from twelve to sixteen parts of water ; one ounce of 

 this liquid is mixed with from ten to fifteen drops of solution 

 of ammonia, and treated with a slow stream of hydi'osulphuric 

 acid ; after half an hour the solution begins to become turbid, 

 and crystals are deposited of the appearance of camphor and 

 of considerable size ; after four or five hours the liquid again 

 becomes clear and the operation is terminated. The crystals 

 are collected on a funnel and washed with water until all the 

 sulphide of ammonium is separated. Pressure between bibu- 

 lous paper removes the adhering water. The diy ciystals are 

 dissolved in aether, the solution mixed with a third of its vo- 

 lume of alcohol and left to spontaneous evaporation. The 

 liquid soon deposits very regular rhombic tables, which can 

 be obtained of half an inch in dimensions if too rapid an eva- 

 poration of the solution has been avoided. 



If no more of the solution is left than is required to cos'^er 

 the crystals formed, the mothei*-liquid is decanted off; the 

 crystals are then dried hy leaving them for some time between 

 folds of bibulous paper. The mother-liquor yields some more 

 thialdine on evaporation. The crystals thus obtained are 

 however not quite colourless. The remaining liquid contains 

 much sulphide of ammonium, part of which arises from the 

 ammonia added. 



It happens sometimes that on passing hydrosulphuric acid 

 gas through the solution of aldehydite of ammonia, no cry- 

 stalline body, but a heavy colourless oil of offensive odour is 

 deposited. This oil is a mixture of two bodies, the greater 

 part being thialdine, the fusing-point of which is depressed 

 to the temperature of the atmosphere by the presence of a 

 liquid substance*. In order to obtain pui'c thialdine from 

 this mixture, the supernatant aqueous layer is separated, and 

 the remaining liquid (consisting principally of the oil and but 

 a small amoimt of the aqueous solution) is agitated with half 

 its bulk of aether, which instantaneously dissolves the oil. 

 The aethereal solution, which may be easily separated from 



• Crystals of thialdino wlicn placed in contact with snlpliidc of ammo- 

 nium for Kome time aru entirely converted into a heavy oil, insuluhlc in 

 water, wliich has not been further examined. 



