ACTION OF CHLOROFORM ON PROTEIDS 
197 
cent, caustic soda, both of these reagents being free from chlorine. The chloroform 
thus becomes converted into hydrochloric acid, forming sodium chloride. About 
fifteen to twenty grams of the moist precipitate are taken and warmed with 1 50 to 
200 c.c. of the permanganate solution in a large beaker, the precipitate being mix.ed 
up as thoroughly as possible with the liquid by frequent stirring. After warming 
the precipitate with this solution for six or seven hours the process is complete, and 
the insoluble matter is filtered off and washed, and the hydrochloric acid estimated 
in the filtrate by silver nitrate after neutralizing the excess of alkali with nitric acid. 
In the case of haemoglobin solutions, where the amount of chloroform added 
was insufficient to cause a precipitate, the proteid was thrown out of solution by 
saturation with ammonium sulphate. The precipitate was then filtered off and 
washed with a saturated solution of that salt, after which it was treated with the 
alkaline permanganate solution, and the hydrochloric acid estimated in the usual way. 
In the case of serum, obtained by centrifulgalizing after allowing the bl ood to 
clot, it was found that it would take up about five per cent, of chloroform. The 
serum becomes very opalescent, even when considerably smaller percentages of 
chloroform are added. 
On centrifugalizing after saturation of the serum with chloroform, no precipitate 
settled out even after three-quarters of an hour, the fluid remaining practically as 
opalescent as at first. If more chloroform was added than the serum could take up, 
on centrifugalizing, the excess of chloroform was precipitated, mixed with only a very 
small quantity of proteid. It was therefore found necessary, in the experiments with 
serum, after allowing it to take up as much chloroform as possible, to precipitate the 
proteid by saturation with ammonium sulphate. Before doing so, however, the 
undissolved chloroform was removed by centrifugalizing. The precipitated proteid, 
after being filtered off, was washed with a saturated solution of ammonium sulphate, 
and the chlorine determined in the same way as in the precipitate from haemoglobin. 
The following shows some of the chief results in the case of haemoglobin 
solutions : — 
Percentage of 
noglobin in solu 
.3-6 
n-5 
12-3 
I5-4 
Percentage of chlorok 
3 
7'5 
entage of chloroform 
1 
i-6 
1-3 
17 
2'2 
