SERALBUMIXS. 253 



contaminated by a glucoproteid. According to LANGSTEIN the sugar 

 is not only mixed with the globulin, but it exists in a combined form, 

 probably in loose combination. 



Serglobulin (the euglobulin) may be easily separated as a fine floc- 

 culent precipitate from blood-serum by neutralizing or making faintly 

 acid with acetic acid and then diluting with 10-20 vols. of water. For 

 further purification this precipitate is dissolved in dilute common salt 

 solution, or in water with the aid of the smallest possible amount of alkali, 

 and then reprecipitated .by diluting with water or by the addition of a 

 little acetic acid. All the serglobulin may also be separated from the 

 serum by means of magnesium or ammonium sulphate; in these cases it 

 is difficult to completely remove the salt by dialysis. As long as we are 

 not agreed as to the number of globulins in the serum, it is not necessary 

 to give a method of separating the various globulins in this mixture. Thus 

 far the fractional precipitation with (NH^SQ^ has been used chiefly. The 

 serglobulin from blood-serum is always contaminated with lecithin and 

 thrombin. A serglobulin free from thrombin may be prepared from fer- 

 ment-free transudates, as sometimes from hydrocele fluids, and this shows 

 that serglobulin and thrombin are different bodies. For the detection 

 and the quantitative estimation of serglobulin we may use the precipi- 

 tation by magnesium sulphate added to saturation (HAMMARSTEN), or by 

 an equal volume of a saturated neutral ammonium-sulphate solution (HoF- 

 MEISTER and KAUDER and POHL x ). In the quantitative estimation the 

 precipitate is collected on a weighed filter, washed with the salt solution 

 employed, dried with the filter at about 115 C., then washed with boiling- 

 hot water, so as to completely remove the salt, extracted with alcohol 

 and ether, dried, weighed, and incinerated to determine the ash. The 

 accuracy of these methods is questionable, as shown by the researches 

 of HASLAM. 



Seralbumins are found in large quantities in blood-serum, blood- 

 plasma, lymph, transudates, and exudates. Probably they also occur 

 in other animal fluids and tissues. The proteins which pass into the 

 urine under pathological conditions consist largely of seralbumin. 



The seralbumin, like the serglobulin, seems also to be a mixture of at 

 least two protein bodies. The preparation of crystalline seralbumin 

 (from horse-serum) was first performed by GURBER. It crystallizes 

 with difficulty from other blood-sera (GRUZEWSKA). Even from horse- 

 serum only a portion of the albumins is obtained as crystals, and it is 

 also possible that the amorphous albumin, which is precipitated by ammo- 

 nium sulphate with difficulty , represents two seralbumins (MAXIMO WITSCH). 

 According to GURBER and MICHEL it would seem that the crystalline 

 serabumin is also a mixture, but this is disproved by the observations 

 of SCHULZ, WICHMANN, and KRiEGER. 2 We know nothing as to the 



1 Hammarsten, 1. c.; Hofmeister, Kauder and Pohl, Arch. f. exp. Path. u. Pharm., 20. 



2 In regard to the literature on the crystalline seralbumins, see Schulz, Die Kristal- 

 lisation von Eiweissstoffen, Jena, 1901; Maximowitsch, Maly's Jahresber., 31, 35. 



