COMPOSITION OF PLASMA AND SERUM. 37 



more abundant; (Edelberg and BirTc). After the injection of ichor into the blood an enormous 

 number of colourless corpuscles are dissolved (F. Hoffmann). The injection of peptone, Hb, 

 and to a less degree of distilled water, is followed by dissolution of numerous leucocytes. 



There are changes in the blood, constituting true blood diseases, in which the physiological 

 metabolism of the colourless corpuscles is enormously increased, so that the metabolic products 

 accumulate in the blood {Alex. Schmidt). The result of this is spontaneous coagulation within 

 the circulatory system, and death even may occur ; there is always an increase of tempera- 

 ture. After such a condition, the coagulability of the blood is diminished. 



31. Formation of Fibrin. After several observers had shown that the red blood-corpuscles 

 (bird, horse, frog) participate in the production of fibrin. Landois observed, in 1874, under the 

 microscope that the stromata of the red blood-corpuscles of mammals passed into fibrin. If a 

 drop of defibrinated rabbit's blood be placed in serum of frog's blood, without mixing them, the 

 red corpuscles can be seen collecting together ; their surfaces are sticky, and they can only be 

 separated by a certain pressure on the cover-glass, whereby some of the now spherical corpuscles 

 are drawn out into threads. The corpuscles soon become spherical, and those at the margin 

 allow the haemoglobin to escape, the decolorisation progresses, from the margin inwards, until 

 at last there remain masses of stroma adhering together. The stroma-substance is very sticky, 

 but soon the cell-contours disappear, and the stromata adhere and form fine fibres. Thus 

 (according to Landois) the formation of fibrin from red blood-corpuscles can be traced step 

 by step. The red corpuscles of man and animals, when dissolved in the serum of other 

 animals, show much the same phenomena. 



Stroma-Fibrin and Plasma-Fibrin. Landois calls fibrin formed direct from stroma, stroma- 

 fibrin ; fibrin formed in the usual way plasma- fibrin. The stroma-fibrin is closely related 

 chemically to stroma itself ; as yet, however, the two kinds of fibrin have not been sharply dis- 

 tinguished chemically. Substances which rapidly dissolve red corpuscles cause extensive coagul- 

 ation, e.g., injection of bile or bile salts, or lake-coloured blood, into arteries. After the 

 injection of foreign blood the newly-injected blood often breaks up in the blood-vessels of the 

 recipient, while the finer vessels are frequently found plugged with small thrombi ( 102). 



Coagulable Fluids.- With regard to coagulability, fluids containing proteids 

 may be classified thus : 



(1) Those that coagulate spontaneously, i.e., blood, lymph, chyle. 



(2) Those capable of coagulating, e.g., fluids secreted pathologically in serous cavities; for 

 example, hydrocele fluid, which, as usually containing fibrinogen only, does not coagulate 

 spontaneously, but it coagulates on the addition of fibrino-plastin and ferment (or of blood- 

 serum in which both occur). 



(3) Those which do not coagulate, e.g., milk or seminal fluid, which do not seem to contain 

 fibrinogen. 



32. CHEMICAL COMPOSITION OF PLASMA AND SERUM. I. Proteids 



occur to the amount of 8 to 10 per cent, in the plasma. Only 0*2 per cent, of 

 these go to form fibrin. After the formation of the fibrin the plasma is converted 

 into serum. The sp. gr. of human serum is 1027 to 1029. It contains several 

 proteids. [According to Hammarsten, human serum contains 9*207 per cent, of 

 solids, of these, 3*103 = serum-globulin, and 4*516 = serum-albumin, i.e., in the ratio 

 of 1 : 1*511. In horse-serum the proportion is 4*5 : 2*6, in ox-serum 4*16 : 3*29, 

 and rabbit-serum 6*22 : 1*78. The total amount of proteids in blood seems to be 

 much more constant than are the relative proportions of serum-albumin and serum- 

 globulin (Salvioli).] 



(a) Serum-globulin or Paraglobulin (2 to 4 per cent.). If crystals of 

 magnesium sulphate be added to saturation to serum at 35 C, serum- globulin is 

 precipitated, but not serum-albumin. It is soluble in 10 per cent, solution of 

 common salt, and coagulates at 69-75 C. Its specific rotatory power is - 47*8 

 (Fredericq). 



[Serum-globulin was described by Panum under the name of "serum-casein"; by Al. 

 Schmidt, as " fibrino-plastic substance"; and by Kiihne, as " paraglobulin. "] During hunger 

 the globulin increases and the albumin diminishes. 



(b) Serum-albumin (3-4 per cent:). Its solutions begin to be turbid at 60 G, 

 and coagulation occurs at 73 C, the fluid becoming slightly more alkaline at the 

 same time. If sodium chloride be cautiously added to serum, the coagulating 

 temperature may be lowered to 50 C. Its specific rotatory power is from -62*6 



