312 THE CHEMISTRY OF BLOOD, I., 



ness, and subsequently fusing M'ith an additional quantity of 

 Na„CO;j and KNO^; the sulphates were precipitated in hot 

 solution by addition of BaCl^. 



The precipitates were collected on filter paper, and, after wash- 

 ing and drying, were ignited, and the ash reheated with a few 

 drf)p8 of concentrated sulphuric acid. 



a) 7111 gi'am globin sulphate gave 01610 gram BaSO S 311% 



(b) 0-7239 gram ,, ,, ,, 0-1747 ,, ,, S 3-29% 



*(c) 0-2285 gram „ ,, „ 00496 „ ,, 8 2-98% 



(d) 0-5500 gram ,, ,, ,, 0-1134 ,, ,, 8 3-01% 



Mean value for sulphur S 3-05% 



Tt was next of importance to determine how much of this 

 sulpluir was present in the globin sulphate as sulphate, and how 

 much as sulphur itself. 



An attempt was made to determine this by difference, but the 

 result was not satisfactory, the percentage of organically combined 

 sulphur being found to be too high. 



The percentage of sulphur was, therefore, determined in a 

 sample of globin 'prepared by precipitation in the absence of 

 sulphuric acid. The result gave 0-45 as the mean percentage of 

 sulphur in globin. From this figure, and the data given above 

 for the total sulphur, in globin sulphate, it is possible to calculate 

 the pro.ximate composition of globin sulphate. 



Experiment i.—The direct determination oj the nrganically 



combined sulphur in globin of ox-blood. 

 Preparation of the globin : 



Alcohol 500cc. 



Ether 200cc. 



Water lOOcc. 



Trichloracetic acid 1 Ograms. 



Ox-blood 50% solution 50cc. 



The blood-sokition was poured into the acid alcohol-ether 

 mixture, and the solution set aside for some days. No pre- 



* I am indebted to Dr. J. M. Petrie, F.I.C., for this sample (c) of globin, 

 which was prepared by him last year. I would express my thanks to him 

 also for many suggestions relating to the Lawrow method. 



