424 BLOOD AND LYMPH. 



found in the serum than in the plasma. This fact is explained by 

 supposing that during coagulation some of the leucocytes disinte- 

 grate and part of their substance passes into solution as a globulin 

 identical with or closely resembling paraglobulin. Paraglobulin as 

 obtained from blood-serum by half saturation with ammonium 

 sulphate or full saturation with magnesium sulphate does not behave 

 like a chemical individual. Portions of it, for instance, are precipi- 

 tated by C0 2 or by dialysis, and portions are not so precipitated. 

 Recently, therefore, it has been assumed that paraglobulin is in 

 reality a mixture of two or possibly three different, although re- 

 lated, proteins. The separation usually given is into euglobulin 

 and pseudoglobulin, euglobulin being the portion precipitated by 

 ammonium sulphate when added to one- third saturation (28 to 33 

 per cent.), and pseudoglobulin the portion precipitated only by 

 one-half saturation (34 to 50 per cent.). The latter portion shows 

 properties more nearly related to the albumins.* The whole basis 

 of classification is, however, unsatisfactory and provisional (see 

 appendix). It is even stated that under certain conditions of 

 temperature and reaction serum-albumin may be converted to a 

 globulin body that precipitates upon one-half saturation with 

 ammonium sulpha te.f The origin of paraglobulin remains unde- 

 termined. It may arise from the digested proteins absorbed from 

 the alimentary canal, but there is no evidence to support such a 

 view. Another suggestion is that it comes from the disintegration 

 of the leucocytes (and other formed elements) of the blood. These 

 bodies are known to contain a small quantity of a globulin resem- 

 bling paraglobulin, and it is possible that this globulin may be liber- 

 ated after the dissolution of the leucocytes in the plasma, and thus go 

 to make up the normal supply of paraglobulin. Several observers! 

 have claimed that during starvation the proportion of globulins 

 in the blood is increased relatively or absolutely. A possible 

 explanation is that the increase is due to cell globulins received from 

 the tissues which must undergo destruction and dissolution in pro- 

 longed fasting. The fact remains, however, that our knowledge is 

 too incomplete at present to venture any positive statements 

 regarding the origin and specific functions of the paraglobulin. 



Fibrinogen is a protein belonging to the globulin class and exhibit- 

 ing all the general reactions of this group. It is distinguished from 

 paraglobulin by a number of special reactions; for example, its 

 temperature of heat coagulation is much lower (56 to 60 C.), and 



* Forges and Spiro, "Beitrage zur chem. Physiol. u. Pathol.," 3, 277, 

 1903; and Freund and Joachim, "Zeitschrift f. physiologische Chemie," 36, 

 407, 1902. 



t Moll, "Beitrage zur chem. Physiol. u. Pathol. " 4, 561, 1903. 



t See St. Githens, "Beitrage zur chem. Physiol. u. Pathol./' 5, 515, 1904; 

 also Lewinski, "Pfliiger's Archiv f. d. 



gesammte Physiol.," 100, 611, 1903- 



