CHEMICAL EXAMINATION OF THE BLOOD. 339 



Rapidity of Coagulation. The rapidity with which coagu- 

 lation of the blood occurs after being shed varies with different 

 animals, with the districts from which the blood is taken, etc. 

 In birds it thus occurs after one and a half minutes ; in man 

 after from three to four minutes ; while in cold-blooded animals 

 it begins only after a quarter of an hour. In the horse, in which 

 coagulation is likewise delayed, the corpuscles of the blood have time 

 to settle and form two distinct layers the red at the bottom and the 

 white on top, where they appear as a grayish-w r hite zone, and con- 

 stitute the so-called crusta phiogistica or inflammatoria. Above this 

 we then see the plasma, which has undergone coagulation, and on 

 top of it the serum that has been squeezed out from the clot. The 

 same phenomenon may be observed in human blood when cooled to 

 about C., and from the extent of the crusta phiogistica (leuco- 

 cytosis) in such blood the older physicians were wont to draw prog- 

 nostic conclusions as to the course of the disease. 



The rapidity of coagulation can be artificially increased and 

 diminished. By beating the blood, by increasing its temperature 

 a little beyond that of the body, and by diluting with water it is 

 increased ; the same occurs after the administration of calcium salts 

 and of gelatine, while exposure to a low temperature, the presence of 

 much carbon dioxide in the blood, the careful lubrication of the 

 vessel with vaselin or similar unguents, cause a retardation of coagu- 

 lation. Its prevention finally may be brought about through influ- 

 ences already mentioned, viz., by salting with the neutral salts, 

 following the previous injection into the body of albumoses or of 

 histon, of diastatic ferments, of extracts of the mouth-parts of the 

 leech, after elimination of the intestinal bloodvessels by ligation, etc. 

 It has been known for a long time also that after the bite of certain 

 snakes the blood does not coagulate. Cobra poison is said to con- 

 tain a substance which acts upon the thrombokinase directly. 



In addition to the albumins already considered, viz., fibrinogen, 

 the serum -albumin, and serum-globulin fraction, and Pekelharing's 

 nucleoproteid (fibrin-ferment), the blood also contains a peculiar 

 albuminous substance which is termed glutolin. It was discovered 

 by E. Faust in the globulin fraction obtained on half-saturation of 

 the blood-serum with ammonium sulphate, and supposedly occupies 

 a position intermediate between the albumins and collagen. Its 

 significance is not known, and it is possible that the substance repre- 

 sents no preformed body, but is a denaturized globulin. 



Glassner and Langstein believe to have shown that albumoses also 

 can occur in the blood under normal conditions; that this is possible 

 in disease has long been known. The occurrence of still other al- 

 buminous substances has from time to time been announced, but has 

 not been satisfactorily established (Eichholz's mucoid, Zanetti's 

 ovomucoid-like body, etc.). 



Ferments. In addition to the fibrin-ferment the blood-plasma 



