198 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
The high percentage of chloroform in the precipitate in the last result is doubt- 
less due to the difficulty in washing away all the excess of chloroform. In the other 
experiments all the chloroform would be taken up, Moork and Roaf finding that 1 
solutions of haemoglobin will take up over 6 per cent, by weight of chloroform. 
These results, considering the nature of the precipitate, seem to show that the 
amount of chloroform taken up in precipitating the proteid from haemoglobin 
solutions is constant, even though widely different percentages of chloroform are 
added, and, therefore, apart from other facts, it would seem that the precipitate 
obtained on adding chloroform to haemoglobin solutions is a definite compound or 
at least a physical aggregation. 
The experiments with serum are more troublesome to carry out, owing to 
the necessity of saturation with ammonium sulphate, and the more thorough washing 
in order to remove the sodium chloride. The results, however, point to a more or 
less constant proportion of chloroform in the precipitated proteid. 
Percentage of chloroform 
Percentage ot chloroform 
in precipitated proteid 
to proteid in the 
serum 
°'5 
2-4 
3-6 
2 
io - 9 
3 
12-3 
5 
I 2 
6 
8 
16 
These figures seem to show that the proteid is not fully saturated with chloro- 
form until the amount of the latter added is between two or three per cent., the 
amount of chloroform in the precipitate with lower percentages being approximately 
proportional to the amount of chloroform added to the serum. 
As serum only takes up about five per cent, of chloroform, the results with six 
and eight per cent, are probably too high, owing to the difficulty in washing away all 
the adherent chloroform. 
An interesting fact was noticed bearing on the stability of the compound between 
chloroform and haemoglobin. If the latter solution is first saturated with carbonic 
oxide, and then 7*5 per cent, of chloroform is added, the solution retains the colour 
of carbonic oxide haemoglobin, but only a very small precipitate, if any, is formed, 
and with, say four per cent, of chloroform, no precipitate appears even on long standing. 
This would seem to prove that chloroform forms a compound which is less stable 
than carbonic oxide haemoglobin, or at least is not formed in the presence of excess 
of carbonic oxide. 
Loc. cit. 
