vin OSMOTIC PRESSURE AND PRECIPITINE REACTIONS 331 



Tamman, 1 Ludeking, 2 Dreser, 3 Koeppe, 4 Krafft and Wiglow, 5 Starling, 6 

 Martin, 7 and Weymouth Reid. 8 



In a more recent paper Weymouth Reid 9 has come to the con- 

 clusion that by washing salted-out or crystallised albumins, solutions 

 are obtained giving no osmotic pressure. The same conclusion the 

 author arrived at previously in his Physiological Histology, in which he 

 gave the reasons why salt-free albumins cannot exert any osmotic pres- 

 sure, for albumins in their natural state are chemically inert, as they do 

 not even react with aniline dyes. They are, in short, in the pseudo-acid 

 pseudo-basic state, forming ring-compounds (see this book, p. 219). If 

 albumins contain any radical which leads to their dissociation, which 

 makes them chemically active, they do possess a definite osmotic 

 pressure, as is instanced by haemoglobin solutions, which Weymouth 

 Reid 10 has found to show no " ultra-microscopic " structure, and thus to 

 differ from serum and egg-albumin, and also to exert a pressure : Taking 

 the molecular weight of haemoglobin as 16,669 (see p. 328), a one per 

 cent solution, assuming that no dissociation occurs, gives a pressure 

 of about 10*77 mm. of mercury at 15 C. 



4. Precipitine Reactions 



Bordet, 11 Wassermann, 12 Myers, 13 and others have found that 

 albumins on being introduced into the blood give rise to specific 

 precipitates as do other colloids, and Ascoli, 14 Umber, 15 Michaelis and 

 Oppenheimer, 16 Schiitze, 17 Hamburger, 18 v. Dungern, 19 and others have 



1 Tamman, Zeitschr. f. physik. Ohem. 2O. 180 (1896). 



2 Ludeking, Ann. d. Phys. u. diem. 35. 552 (1888). 



3 Dreser, Arch. f. experimen. Pathol. u. Pharmak. 29. 314 (1892). 



4 Koeppe, Pfliiger's Arch. 42. 571 (1896). 



5 F. Kraft and H. Wiglow, Ber. d. deutsch. chem. Ges. 28. 2566 (1895). 



6 Starling, Science Progress, April 1896 ; Journ. of Physiol. 19. 312 (1896) ; ibid. 

 24. 317 (1899); Schafer's Textbook of Physiol. 1. p. 307. 



7 Martin, Journ. of Physiol. 2O. 317 (1896) ; ibid. p. 364. 



8 Weymouth Keid, ibid. 27. 161 (1901). 



9 E. Weymouth Reid, ibid. 31. 438 (1904). 



10 Idem, ibid. 33. 12 (1905). 



- u Bordet, Ann. de Vlnstitut Pasteur, 1899, p. 232. 



12 Wassermann, Kongress f. innere Medizin, 1900, p. 501 ; Miinchener medizin. 

 Wochenschr. 1900, II. p. 986. 



~ 13 W. Myers, Zentralbl. f. Bakteriol. 28. 237 (1900). 

 ~ 14 M. Ascoli, Miinchener medizin. Wochenschr. 1902, I. p. 398 ; 1903, Nr. 5. 



15 F. Umber, Berliner klin. Wochenschr. 1902, Nr. 28. 



- 16 L. Michaelis and C. Oppenheimer, Arch. f. (Anat. u.) Physiol. 1902, Suppl. 

 p. 336 (here also the older literature) ; L. Michaelis, Deutsche medizin. Wochenschr. 

 1902, Nr. 41. 17 A. Schutze, ibid. 1903, Nr. 45. 



- 18 F. Hamburger, Wiener klin. Woclienschr. 1901, Nr. 49 ; 1902, Nr. 45. 

 19 E. v. Dungern, Die Antikorper, Jena, Fischer, 1902. 



