PROFESSOR LETTS ON PHOSPHORUS-BETAINES. 30D 
Now, in addition to having a strong affinity for bromine, phosphorus has if 
anything a greater attraction for oxygen, whilst its affinity for carbon is slight, 
so that it is almost surprising that 
: Br 
(CH,)s= PC 
CH, — COOH 
should be capable of existence at all. And it is certainly a remarkable feature 
in the history of these substances that this body should lose oxygen when 
heated (in the form of carbonic acid). It might rather be expected that it 
would, when heated, be converted into the aceto-bromide. But all attempts 
made in this direction have been unsuccessful. 
In conclusion, I have to express my thanks to my assistant, Mr N. Cotte, 
for the assistance he has rendered me during these experiments. 
