THEORIES OF CO A G ULA TION. 1 7 1 



digesting these with calcium chloride, the excess of calcium salt being 

 afterwards dialysed off. Pekelharing supposes that the ferment action 

 consists in the transference of lime from its nucleo-proteid combination 

 to fibrinogen, the lime-compound of this being the insoluble fibrin, 1 and 

 that if there is more lime salt in the solution the nucleo-proteid can 

 recombine with lime, and thus become reconstituted as an agent for the 

 conversion of fibrinogen into fibrin. As already pointed out (p. 166), 

 however, it is not possible to accept this theory in view of the analyses 

 of fibrin and fibrinogen given by Hammarsten. Pekelharing has himself 

 shown that even in the entire absence of free lime salts, or in the 

 presence of soluble oxalates, the transformation of fibrinogen into fibrin 

 may be produced, provided that the ferment is present. 2 This has also 

 been shown to be the case by A. Schmidt 3 and by myself, 4 and more 

 recently in a series of carefully conducted experiments by Hammarsten. 

 Hammarsten precipitated fibrinogen by oxalated solution of salt, and, 

 after purifying it by repeated re-solution and re-precipitation, added to 

 its solution a fibrin ferment obtained from oxalated serum, and obtained 

 as the result a typical fibrin. 5 



Exception has been taken to the inference drawn by Pekelharing that 

 Schmidt's ferment is a compound of nucleo-proteid and lime, on the ground 

 that the ferment contained in Schmidt's extract differs from nucleo-proteids 

 in the effect of alcohol upon its solubility in water, and in the fact that 

 nucleo-proteids cause coagulation in intravascular plasma, which Schmidt's 

 extract does not, whereas the latter causes coagulation in extravascular (salted) 

 plasma, and nucleo-proteids do not. 6 The ^ differences may, however, depend, 

 in part at least, upon the relative amounts of nucleo-proteid and lime. Thus 

 in Schmidt's extract the amount of nucleo-proteid is small and the amount of 

 lime large ; in extracts of thymus and the like the amount of nucleo-proteid 

 is large and the amount of lime small. In part also they depend upon other 

 circumstances, such as the influence of the magnesium sulphate of the salted 

 plasma in antagonising the effect of lime. 7 



The origin of the nucleo-proteid of plasma and serum is probably the white 

 corpuscles. It would appear that many of the latter disintegrate after removal 

 of blood from the body. Giirber 8 found that in coagulated blood the number 

 of white corpuscles was reduced to one-half, the difference being chiefly in the 

 number of polynuclear cells. This disappearance has not, however, been 

 found by all observers, and is not fully admitted. Nevertheless, without 

 actually disintegrating, the white corpuscles may shed out or secrete nucleo- 

 proteid into the plasma. This may occur normally in mere traces, but on with- 



1 Centralbl.f. Physiol., Leipzig u. Wien, 1895, No. 3. 



2 It would appear that a soluble oxalate does not throw down all the lime from a proteid- 

 containing fluid, and that a trace of lime is still held in solution so that an oxalate plasma 

 is not lime-free, as was supposed by Artlras and Pages. This is well illustrated by an 

 observation by Ringer upon the frog's heart, who finds that a normal saline solution, 

 to which a little CaCl 2 has been added, will exhibit the physiological effect of lime, 

 even after the addition to the fluid of a slight excess of a soluble oxalate. It may be 

 inferred from this that a trace of lime may be held in solution even in a fluid destitute of 

 proteid. 



3 " Weitere Beitr. z. Blutlehre," Wiesbaden, 1895. 



4 Proc. Physiol. Soc., Journ. Physiol., Cambridge and London, 1895, vol. xvii. 

 p. xviii. 



5 Ztschr. f. physiol. Chem., Strassburg, Bd. xxii. 



6 Hnlliburton and Brodie, Journ. Physiol.. Cambridge and London, 1894, vol. xvii. p. 143. 



7 Pekelharing, Centralll f. Physiol.', Leipzig u. Wien, 1895, Bd. ix. S. 102. Halliburton 

 in a recent paper (Journ. Physiol., Cambridge and London, 1895, vol. xviii.) comes to a 

 similar conclusion, namely, that Schmidt's fibrin ferment is a weak solution of nucleo- 

 proteid. It produces Wooldridge's negative phase when intravenously injected. 



8 Sitzungsb. d. phys.-med. Gesellsch. zu Wilrzburg, 1892, No. 6. 



