162 



THE BLOOD. 



nium sulphate. The globulins and nucleo-proteids are completely pre- 

 cipitated by half-saturation with ammonium sulphate, or by complete 

 saturation with magnesium sulphate ; whilst fibrinogen is precipitated 

 by half -saturating plasma with chloride of sodium (probably some nucleo- 

 proteid is carried down with it). Upon these differences of solubility in 

 solutions of neutral salts the separation of the blood-proteids one from 

 another depends. 



The proportion of globulin to albumin & ~ is known as the " proteid 



albumin 



quotient " ; it varies in different animals and in the same species of animal 

 under different conditions. 1 For the same individual it is almost constant in 

 the blood serum, lymph, and serous transudations, although the absolute 

 amount of proteid in these may vary greatly. 2 



The annexed table 3 shows the total and relative amounts of the proteids 

 in the serum of different animals. The numbers are taken from different 

 sources ; the first four from Hammarsten. 4 



They are obtained (a) the total proteids, by weighing the alcohol 

 precipitate; (b) the globulin, by separating off the magnesium sulphate 

 precipitate, re-dissolving this and weighing its alcohol precipitate: (c) the 

 albumins, by taking the difference between these two results. (6) includes, 

 besides serum globulin, a globulin formed from fibrinogen in coagulation, and 

 also the nucleo-proteids of plasma, but both of these are in very small amount. 



The most noteworthy feature shown in these figures is the relatively 

 small amount of albumins present in the serum of cold-blooded animals 

 as compared with the globulins. It has been stated that the albumins 

 proportionately diminish in starved animals, 5 but other investigators 

 have failed to confirm this conclusion. 6 



1 Compare Frassineto, Arch. ital. de biol., Turin, 1895, vol. xxiv. p. 457 ; Paulesco, 

 Arch, de physiol. norm, et path., Paris, 1897, p. 21 ; W. Engel, Arch. f. Hyg., Miinchen 

 u. Leipzig (4), Bd. xxviii. S. 334. 



2 Salvioli, Arch. f. Physiol., Leipzig, 1881, S. 269 ; Hoffmann, Arch. f. exper. Path. u. 

 Pharmakol. , Leipzig, 1882, Bd. xvi. S. 133. 



3 Halliburton, Journ. Physiol., Cambridge and London, 1878, vol. vii. p. 321. 



4 Arch.f. d. ges. Physiol., Bonn, 1878, Bd. xvii. S. 413. 



5 Tiegel, ibid., 1880, Bd. xxiii. S. 278 ; Bnrckhardt, Arch.f. exper. Path. u. Pharmakol. , 

 Leipzig, 1883, Bd. xvi. S. 322. 



6 Salvioli, Arch. f. Physiol., Leipzig, 1881, S. 269 ; Ho well, John Hopkins Univ. 

 Stud. Mol. lab., Baltimore, vol. iii. p. 49; Rubbrecht, Trav. du lab. de L. Fredericq 

 tome v. p. 121. 



