170 THE BLOOD 



inferred that the presence of a soluble salt of lime is necessary to the 

 formation of fibrin, which, according to them, is produced by a combina- 

 tion, under the influence of fibrin ferment, of a part of the fibrinogen 

 with lime, the remainder of the fibrinogen which is assumed to split 

 into two parts forming a globulin coagulating at 64 C. (Hammarsten's 

 fibrino-globulin). 1 



Whilst it would appear from these researches that soluble lime salts are 

 necessary to the formation of fibrin, 2 it has been shown by Home that the 

 presence of a slight excess of these salts and also those of barium and strontium 

 will hinder or, in great amount, entirely prevent its formation ; their action 

 being far more marked in this respect than that of other neutral salts, which 

 require to be mixed in much greater amount with blood to prevent its co- 

 agulation. 3 The reason for this is probably to be found in the fact that fibrin 

 is soluble to some extent in neutral salts of a certain strength (including salts 

 of calcium, barium, and strontium). 



Influence of nucleo-proteid. Theory of Pekelharing. Halliburton 4 and 

 Pekelharing 5 both obtained from Schmidt's extract a body giving proteid 

 reactions, and resembling in many particulars the globulins, to which 

 class of proteids they at first regarded it as belonging. 6 They showed 

 that the ferment action of Schmidt's extract is intimately dependent 

 upon the presence of this substance, which could also, as Halliburton 

 showed, be obtained from lymphatic glands. Halliburton termed it 

 cell globulin ; subsequently both observers recognised the fact that the 

 substance in question was not a true globulin but a nucleo-proteid. 7 

 According to Pekelharing, it possesses the property of combining with 

 lime, which it does not yield to distilled water by dialysis, nor is the 

 combination broken up by soluble oxalates, although these, if present 

 from the first, may prevent the original combination. The albumose in 

 commercial peptone also prevents such combination, the albumose itself 

 combining with the lime salts present ; 8 if these are in excess, " peptone " 

 does not prevent coagulation from taking place. The lime combination 

 of nucleo-proteid is, according to Pekelharing, the body which has been 

 known as fibrin ferment (thrombin). It can be formed not only from 

 the nucleo-proteids contained in plasma or serum, but also from nucleo- 

 proteids in the cells of the thymus, testicle, and other glands, by 



1 Artlms and Pages found that strontium can replace lime in this reaction, but that 

 barium and magnesium cannot. Ringer and Sainsbury have, however, shown that barium 

 may take the place of lime in promoting coagulation, although it is less powerful (Journ. 

 PhysioL, Cambridge and London, 1890, vol. xi. p. 369). They also found that the salts of 

 sodium and potassium act antagonistically to those of lime, barium, and strontium. 



2 A. Schmidt, even in his last communication upon the subject ("Weitere Beitr. z. 

 Blutlehre," Wiesbaden, 1895), denied altogether that lime salts have any specific action 

 or differed from other neutral salts, and considered that the addition of a soluble oxalate to 

 blood acts either by preventing the formation of fibrin ferment or by hindering the action 

 of ferment, if present, on fibrinogen. Cf., however, Arthus, Arch, de physiol. norm, ct 

 path., Paris, 1896, and Hammarsten, loc. cit. 



3 Journ. PhysioL, Cambridge and London, 1896, vol. xix. p. 356. Wright also noticed 

 the fact that considerable excess of calcium added to oxalate blood prevents coagulation, 

 Journ. Path, and Bacterial., Edin. and London, 1893, vol. i. p. 434. 



4 Proc. Roy. Soc. London, 1888, vol. xliv. p. 255. 



5 Festschr. Rudolf Virchow, Berlin, 1891, S. 435. 



c Lilienfeld has recently repeated this error, Ztschr. f. physiol. Chem., Strassburg, 

 Bd. xx. 



7 Pekelharing, "Untersuch. ii. d. Fibrin- ferment," Amsterdam, 1892; Halliburton, 

 Journ. Phijsiol., Cambridge and London, 1895, vol. xviii. p. 312. 



8 Pekelharing. Cf., however, C. J. Martin, "Venom of Australian Black Snake," 

 pp. 36-40, Journ. and Proc. Roy. Soc. New South Wales, Sydney, July 3, 1895. 



