68 ENZYMES OR SOLUBLE FERMENTS. 



globulins m solution, as also does^the similar extract which may 

 be equally efficiently prepared from ordinary washed fibrin. 1 



In no case as yet has the fibrin-ferment been obtained in a con- 

 dition of such purity as to justify any dogmatic statement as to Its 

 chemical composition. All the solutions whose preparation has been 

 described above ^leld strong proteid reactions, and Halliburton 2 

 has argued from his own experiments and a criticism of preceding 

 work that the ferment is really a proteid identical (?) with what 

 he had previously called ' cell-globulin ' (antea, p. 28). On the 

 other hand it is possible by appropriate methods to free the .^alt- 

 extracts of fibrin very completely from proteids without anv great 

 loss of ferment activity, certainly without any such loss as would 

 necessarily be the case if the active substance were a globulin. 3 

 It may be said that the apparent ferment-powers in such cases 

 are in reality due to the presence of calcium sulphate, which is 

 now known to promote the clotting of a dilute salt-plasma to an 

 extraordinary degree ; 4 but as against this the fact may be quoted 

 that solutions free from proteid reaction, and which had been 

 freed from salts by careful dialysis, lost their activity on heating 

 to 60 70, which they would not have done had the activity 

 been due merely to calcium sulphate. 



When Schmidt's method is applied to blood received directly 

 from an artery into an excess of alcohol no ferment can be ob- 

 tained from the precipitate thus obtained. LtL is. hence evident 

 that the living, circulating blood contains no preformed ferment. 

 and the question thus arises from what does it take its origin 

 during the clotting of blood and presumably as an immediate 

 antecedent to that clotting ? Buchanan held distinctly the view 

 that the active agent in the whole process was in some way con- 

 nected with, if not derived from, the white corpuscles, a view also 

 held later on by Mantegazza. Schmidt also took this view, bas- 

 ing it on an elaborate series of investigations for which his orig- 

 inal works must be consulted. 5 Lowit, experimenting with 

 lymph as well as blood, while denying that the white corpuscles 

 break down at clotting in the way Schmidt described, still connects 

 them with the production of the initiative factor in the whole 

 process. 6 Still further evidence in the same direction may be 

 derived from the experiments of Rauschenbach 7 and Halliburton, 8 

 and of Fano, who observed that wTien "peptone-plasma is freed' as 



1 Lea and Green, Jl. of Physiol. Vol. iv. (1883), p. 386. 



2 Jl. of Physiol. Vol. ix. (1888), p. 265. 

 8 Lea and Green, loc. cit. 



* Green, Ibid. Vol. vm. (1887), p. 354. 



5 Pfluger's Arch. Bd. ix. (1874), S. 353; xi. (1875), Sn. 291, 515. 



6 Sitzb. d. Wien. Akad. (2 Abth.), Bd. LXXXIX. (1884), S. 270; xc. S. 80. 



7 Inaug.-Diss. Dorpat, 1883. See also the Dissertations (Dorpat) of F. Hoffmann, 

 1881. Samson-Himmelstjerna, 1882; Heyl, 1882. 



8 loc. cit. See also Kriiger, Zt.f. Biol. xxiv. (1888), S. 189. 



