390 



Prof. B. Moore and Mr. H. E. Roaf. [Apr. 12, 



chloroform, and it need only be mentioned here that we have 

 obtained solubilities of 0'95 per cent., in normal saline (0*75 per cent.), 

 3*33 per cent, in serum and 4 "42 per cent, in whipped blood, by this 

 method. 



The second method employed consists in weighing out known 

 amounts of chloroform into water and serum and haemoglobin solution 

 respectively, and then determining by direct observation that con- 

 centration in each case at which the chloroform ceased to be dissolved. 



This method of observation is made easy in the case of chloroform 

 by the high specific gravity of that fluid, as a result of which on 

 inverting the flask in which the determination is being made even 

 minute globules of undissolved chloroform can be seen falling through 

 the fluid. 



The determinations of solubility by this method are made on the 

 following plan. Pure chloroform is dropped from a fine capillary 

 pipette into a tared graduated flask of 25, 50 or 100 c.c, and carefully 

 weighed to definite amount, corresponding, when the flask has been 

 filled by the solvent under experiment, to a definite percentage of 

 chloroform. A series of such flasks is prepared, and immediately 

 after each flask is filled with the desired solvent and either 

 shaken thoroughly by hand until solution is complete, or placed 

 on a rotary shaking machine. After the lapse of several days, during 

 which time the flasks are never opened and are kept shaken up, it is 

 noticed at what level of concentration the chloroform ceases to be 

 completely dissolved, and so the solubility is determined. 



The lower strengths of known value short of saturation, and also 

 the saturated solutions so j)repared, were kept and used also for the 

 experiments on vapour pressure at varying concentration described in 

 the next section of this paper. 



The following results were obtained by the application of this 

 method at room temperatures, approximately (13° C), for the percentage 

 hy weight dissolved : — 



Water, 0'8 per cent, dissolved, - 9 per cent, dissolved, 1 per cent, 

 not dissolved completely. Estimated solubility 0*95 per cent. 



Saline Solution (0'75 per cent, sodium chloride in water), 0'7 per 

 cent, dissolved, 0'8 per cent, dissolved, 0*9 per cent, not dissolved. 

 Estimated solubility about 0*83 per cent. 



Serum, 3 per cent, dissolved, 3*5 per cent, dissolved, 4 per cent, all 

 dissolved save a few small globules. 



HcemogloUn Solution or Blood. — Over 6 per cent, by weight is taken 

 up when chloroform is shaken with blood or haemoglobin solution of 

 equal strength to the blood, prepared from blood by centrifugalising 

 several times with saline, and subsequent laking with distilled water, 

 and no globules of chloroform can be seen on careful examination 

 with the microscope. But the solution rapidly changes in colour, and a 



