CHAP. II.] THE BLOOD. 39 



salt (from 0*03 to 0'5 or 07 p. c.) be added to a very feebly alkaline 

 solution of paraglobulin this body is precipitated, but on a further 

 addition of salt the precipitate re-dissolves, only to be again 

 precipitated when the amount of sodium chloride exceeds about 

 20 p. c. 



Solutions of paraglobulin (as for example in NaCl) coagulate at 

 temperatures varying between 68 and 80 C., most commonly at 

 75 C., the variations being due to the amount of sodium chloride 

 present, to the duration of the process of heating, and perhaps to 

 other circumstances. (Weyl 1 , Harnmarsten 2 , Frederique 3 .) 



Moderately concentrated solutions of paraglobulin are not pre- 

 cipitated by the addition to them of 16 20 p.c. of NaCl (Ham- 

 marsten 4 ). 



Serum-globulin is said to diffuse with considerable ease through 

 animal membranes. On the other hand, it is absolutely unable to 

 pass through parchment paper. 



The term paraglobulin sufficiently indicates that this body belongs 

 to that group of proteids of which the first well-known member was 

 the proteid constituent of the crystalline lens to which the name of 

 Globulin was given. 



Because of its assumed co-operation in the formation of fibrin, the 

 term fibrinoplastic substance was ascribed to it by A. Schmidt, but, 

 as will be shewn in the section on coagulation, there are no longer 

 grounds for ascribing this function to pure paraglobulin. 



Paraglobulin is not only found in the plasma and in the serum, 

 but it is a constituent of the colourless and coloured (?) blood- 

 corpuscles, of the lymph, chyle, &c. 



According to A. Schmidt's more recent views, the paraglobulin 

 of the serum is derived from the colourless corpuscles of the liquor 

 sanguinis, which in breaking down liberate this constituent, and the 

 body known as the fibrin-ferment. Hammaisten, whilst not denying 

 that a portion of the paraglobulin of serum may be derived from 

 the colourless corpuscles, does not believe that it all takes its origin 

 in this manner, for he has found the plasma to contain large 

 quantities of paraglobulin; he is moreover inclined to think that 

 some portion of the globulin found in serum may be derived from 

 the decomposition of fibrinogen. The Swedish observer has found 

 that when a solution of pure fibrinogen coagulates, besides fibrin, 

 there is formed a soluble proteid which belongs to the group of 

 globulins, and which therefore, if present in the serum, would be 

 reckoned as paraglobulin. 



The view has been held by Brlicke and Heynsius, that para- 



1 Weyl, "Beitrage zur Konntniss thierischer und pflanzlicher Eiweisskorper," 

 Pfluger's Archiv, Vol. xn. p. 635 638. 

 1 Hammarsten, loc. cit., p. 64. 



3 Frederique, Recherchcs sur la constitution du Plasma Sanynin. Gand, 1878. 



4 Hammarsten, "Zur Lehre von der Faserstoffgerinnung," Pfluger's Archiv, Vol. 

 xiv. (1877) p. 224. 



