614 DR. E. A. LETTS ON THE 
Action of Sulphide of Allyl on Bromacetic Acid—The next experiments — 
tried were with allyl-sulphide—the oil of garlic. 
In a preliminary experiment, a little sulphide of allyl was warmed with brom- 
acetic acid. The latter dissolved, but no separation of oily liquid occurred — 
(characteristic of the production of a thetine compound), nor was any change 
apparent. After about a week, however (during which the mixture remained 
at ordinary temperatures), it became very syrupy, and warty crystals were 
deposited, which increased in quantity when the liquid was shaken. In a 
second experiment 6 grms. of allyl-sulphide (mol. wt. 114), and 7 grms. of 
bromacetic acid (mol. wt. 139), carefully dried between blotting paper, were 
placed in a test tube, and the mixture simply shaken, and not warmed. Most 
of the bromacetic acid dissolved, but some remained undissolved even after a 
day’s contact with the sulphide. On the second day all had dissolved, and 
there remained two layers of liquid—the lower oily and slightly brown; the 
upper much more mobile and lighter in colour. In two or three more days 
the upper layer had nearly disappeared, being absorbed into the lower. After — 
a week or two, crystalline nodules appeared in the liquid, and gradually 
increased in quantity. From time to time the liquid was poured off from these, 
and allowed to remain at rest, when more and more of the crystals separated. 
After about five weeks it was judged that the reaction was complete. 
A. portion of the crystals which had separated out was washed with ether 
(to remove adhering sulphide of allyl and bromacetic acid), then dissolved in 
water, the solution neutralised with caustic baryta, and evaporated somewhat. - 
On cooling, the characteristic barium salt separated out, which was idenua 
as thiodiglycollate by a determination of barium— 
‘1213 germs. gave 0748 sulphate of baryta = 36:3 per cent. barium, 
S(CH,CO,),Ba,5H,O requires. : 2 SOD as 
Another portion of the crystals was dissolved in water, and precipitated 
with acetate of lead. On warming the mixture, the amorphous flocculent salt at 
first precipitated dissolved, but was rapidly replaced by crystalline spangles. 
This réaction, as before mentioned, is characteristic of thiodiglycollic acid. 
The lead was determined in the spangles by heating them with sulphuric acid— 
‘135 grms. gave ‘114 sulphate of lead = 57°6 per cent. lead 
S(CH,CO,),Pb requires . 5 pi Me ee 
The liquid products of the action of sulphide of allyl on bromacetic acid were 
distilled in a current of steam, and yielded at first an oily liquid heavier than 
water (bromide of allyl, sp. gr. 1-4)—later an oily liquid lighter than water (sul- 

