CHEMICAL EXAMINATION OF THE BLOOD. 331 



ammonium sulphate, or on complete saturation with magnesium 

 sulphate, an albuminous precipitate is obtained, which was formerly 

 regarded as a unity and termed serum-globulin (sive paraglobulin, 

 serum-casein, Schmidt's fibrinoplastie substance). Later researches 

 have shown that this consists of several distinct bodies, and for this 

 reason it would be better to discard the term serum-globulin as such, 

 and to speak of a serum-globulin fraction. The most notable com- 

 ponents of this fraction are euglobulin and pseudoglobulin. The 

 former is precipitated in the presence of 28-34 per cent, of am- 

 monium sulphate, while the latter is thrown down with 36-44 per 

 cent. These two fractions further differ from each other in the 

 behavior of their saline solutions on dialysis. The euglobulin is 

 thus thrown down while the pseudoglcbulin remains in solution. 



Fuld and Spiro have shown that the coagulating effect which blood 

 produces on milk is referable to the euglobulin fraction, while the 

 anti-action is a property of the pseudoglobulin. Pick has demon- 

 strated still a further difference ; in horses immunized to diphtheria 

 the antitoxic properties of the serum are connected with the pseudo- 

 globulin while the other fraction is inert. In the case of the 

 opsonins I have shown that they are associated with the euglobulin 

 fraction. 



As the two fractions in their general properties are otherwise 

 apparently identical, it has been suggested that the difference in their 

 behavior to ammonium sulphate and on dialysis, etc., might possi- 

 bly be due to a third factor. Morner thus thinks that contamina- 

 tion of the globulin precipitate by soaps, fatty acids, lecithins, etc., 

 is the determining factor in this respect. The majority of physio- 

 logical chemists, inclusive of Hammarsten, who has been especially 

 active in this field, however, incline to the view that serum-globulin 

 represents a mixture of at least two or more bodies. 



Freund and Joachim have further pointed out that from both 

 euglobulin and pseudoglobulin they could obtain one fraction which 

 was precipitated on dialysis and a second one which remained in 

 solution. The water-insoluble portion of each fraction they desig- 

 nate as para-euglobulin and para-pseudoglobulin respectively, while 

 the terms euglobulin and pseudoglobulin are retained for the water- 

 soluble portion of each fraction. 



Serum-globulin, using the term in the older sense of the word, is 

 found not only in the plasma of the blood, but also in the lymph, in 

 various exudates and transudates, in the serum, in the white and red 

 corpuscles of the blood, and in traces at least in all the cellular ele- 

 ments of the body (cell-globulins). In the urine serum-globulin 

 usually accompanies serum-albumin. 



Properties. As a class the serum-globulins represent a snowy- 

 white, finely flocculent material, which is not tough and elastic like 

 fibrinogen. They have not been obtained in crystalline form. In 

 water the euglobulins are practically insoluble, while the pseudo- 

 globulins will dissolve. The insolubility in water was formerly 



