586 DR E. A. LETTS ON THE 
standing. Although there can be no doubt that the syrupy liquid consists 
essentially of sulphate of diethyl-thetine— 
C,H, C,H; 
H000—CH,—$80,—4CH,—COOH. 
C,H, bx, 
owing to the impossibility of obtaining the salt in the crystalline state, it was 
not further examined. 
Diethyl-Thetine Base.—Some of the hydrobromate was dissolved in water, 
and oxide of silver added to the solution until it ceased to be converted into 
bromide. The solution was then filtered, a few drops of hydrochloric acid added 
to precipitate any silver that remained in the solution, and the latter again 
filtered. It was then concentrated in a desiccator, and finally remained fer 
some weeks over phosphoric anhydride. It, however, simply dried up to a 
very thick syrupy liquid and refused to crystallise. The base, no doubt, has 
the composition expressed by the formula— 
C,H, 
HO—S—CH,—COOH. 
| 
C,H, 
but the syrup was not thought sufficiently pure for analysis. 
Hydrobromate of Dipropyl-Thetine.—Sulphide of propyl was prepared by 
digesting for some time in a flask provided with an upright condenser—chloride 
of propyl* and alcoholic solution of sulphide of potassium. The mixture 
was heated in a water-bath for three or four hours, then left for a night, and 
distilled. The sulphide of propyl contained in the distillate was separated 
with water, filtered, and employed without further purification ; 6-5 erms. of 
the sulphide thus prepared, and 6°5 grms. of bromacetic acid + (carefully dried 
between filter paper), were mixed and shaken. The acid dissolved with fall of 
temperature, and after a few minutes the mixture grew cloudy, and soon a 
dense syrupy layer separated, which gradually increased in quantity, This 
did not, however, show any signs of crystallising even after several days’ 
standing, nor was any change effected by cooling it in a freezing mixture. 
* ‘The specimen employed was from Kantpavm of Berlin. 
+ Equimolecular quantities require for 6°5 of bromacetic acid 5°6 of propyl sulphide. 

