312 PROFESSOR LETTS ON PHOSPHORUS-BETAINES, 
Very different is the behaviour of the thetines and their compounds when 
heated. 
The author’s experiments extended to dimethyl-thetine itself and to its salts 
with oxyacids and with hydracids. It will be sufficient to say that all the 
former appear to be decomposed in a similar manner, but that the latter suffer 
a totally different kind of decomposition. 
The free base and its oxysalts always yield carbonic anhydride, and a salt 
of trimethyl-sulphine. Its haloid salts give, it is true, a trimethyl-sulphine 
compound, but this is accompanied by thio-diglycollic acid and a haloid ether 
of methyl. 
The decomposition which the free base, its sulphate, and its hydrobromate 
suffer will render this clear. 
CH,—COOH 
(1) 2} (CH= ee | = | (CH,),S},00, + H,O + CO,. 
CH, {C00 H 
(CH,),= — | (CH,),=8--CH,, 
(2) be SO, + 2CO,, 
(CH,) < wy (CHS 
*"\on,— coon °° SCH, 
and 
Br 
(CH), =8¢ 
CH,—COOH CH,—COOH 
(3) 3 SC + CH,Br + (CH,),SBr. 
CH,—COOH CH,—COOH 
(CH,),= SC 
Action of Heat on Ethyl-Bromate of Triethyl-Phosphorus-Betaine.* 
Several experiments were made on the action of heat on this body (which 
was always prepared by adding triethyl-phosphine to an ethereal solution of 
bromacetic ether). The results were similar, but as the products were not in 
each case completely investigated, it will be more convenient to give a summary 
of the experiments. 
The ethyl-bromate was heated in a distilling flask connected with the 
* The first of the author’s experiments on the action of heat on the compounds of triethyl- 
phosphorus-betaine was made with this body. At the time he had only studied the action of bromacetic 
acid and of bromacetic ether on triethyl-phosphine, and consequently was unacquainted with any salts 
of the phosphorised betaine (see pp. 300, 301). The experiments with the ethyl-chlorate and hydro- 
chlorate were made more than a year afterwards, 
