COAGULATION OF BLOOD OF ARTHROPODS. 3O/ 



If, instead of the shreds of the first coagulation, the gelatinous 

 coagulum of the second is added to the ordinary serum, effi- 

 ciency of the latter fibrin is usually found not to be as pronounced 

 as that of the first fibrin. 



Foreign bodies, as such, added to the serum in place of fibrin 

 or muscle, do not tend to accelerate coagulation. In no case 

 could any marked influence be observed. Also platinum black 

 was without any effect. 



On the surface of the blood serum, kept in open dishes, usually 

 a film is formed. This surface film in most cases radiates from 

 the shreds of fibrin put into the serum. If we shake the serum 

 for one half hour in dishes with uneven surfaces, macroscopically, 

 visible membranes of fibrin are formed. 



Extract of fibrin, which was previously kept in absolute alcohol, 

 or of fresh fibrin under addition of chloroform water, have so far 

 not shown an efficiency comparable to that obtained by the addi- 

 tion of fresh fibrin itself. One cubic centimeter of such an extract 

 added to 4 cc. of serum, in most cases only caused a very insignifi- 

 cant acceleration of the coagulation in comparison to serum to 

 which i cc. of a 6 per cent, sodium chloride solution had been 

 added. Halliburton states that an extract of mammalian blood 

 precipitated in alcohol and afterwards dried, produced coagulation 

 in blood which had been collected in a magnesium sulphate solu- 

 ion. I did not succeed in producing coagulation in this way ; such 

 a result would be contradictory to the one obtained by myself with 

 the fibrin of rabbits and rats. 



We may explain all these facts by the supposition that in the 

 shreds produced by the first coagulation there is present a fer- 

 ment or pro-ferment producing coagulation, and further, that 

 such a ferment or pro-ferment must be present inside of the 

 blood cells, because the first clot consists mainly of blood cor- 

 puscles and parts of these cells. Further, we are certain of the 

 decidedly localized action of this ferment, as directly around the 

 shreds of fibrin the second gelatinous fibrin is deposited. This 

 can be explained by the assumption that the ferment can only 

 slowly diffuse into the fluid ; it must however nevertheless be 

 able to diffuse through the gelatinous substance formed around 

 the shreds, although as recent experiments seem to prove, even 



