28.2 
DIFFUSION, OSMOSIS, AND FILTRATION. 
1. Egg albumin — 4*14 per cent, proteids ; pressure, 32-5 cm.; goldbeater's skin. 
(Filtrate per minute in grins., "820, "051, -008, '003, '002, -002.) 
2. Ox serum — 4-5 per cent, proteids ; pressure, 30*5 to 34 cm. ; goldbeater's skin. 
(Filtrate per minute in gnus., 2-586, 1-594, 1-000, -812.) 
In neither case had the membrane been previously stretched. 
According to Gottwalt, 1 the serum albumin of blood serum filters 
through a ureter more easily than the globulin. Martin 2 has shown 
that homogeneous membranes of gelatin and gelatinous silicic acid form 
filters impermeable to solutions of many colloids, but as permeable 
to certain crystalloids as to water. 
The relation of the concentration of the filtrate to that of the 
original solution is perhaps the most important point to the physiolo- 
gist in the matter of filtration through animal membranes. There is 
general agreement that in the filtration of crystalloids the concentration 
of the filtrate is very nearly that of the original solution, and this 
appears to obtain at very various filtration pressures. 3 There is also 
general agreement that in filtration of colloids the concentration of the 
filtrate is always less than that of the original solution. 4 But as regards 
the effect of pressure on the concentration of a colloid filtrate, the 
results of different observers are not in accordance. Eimeberg 5 has 
maintained that the concentration of the filtrate is higher at lower 
than at higher pressures, and the following table, taken from his later 
paper, 6 is illustrative : — 
Fresh Sheep's Intestine — Ascitic Fluid (circulated) holding 
3'72 per cent, of Proteids. 
Time. 
Pressure in Cm. 
of Fluid. 
Filtrate per hour 
in Grins. 
Per Cent. Albumin 
in Filtrate. 
8 P.M. to 8.15 A.M. 
8.15 A.M. to 2.15 P.M. . 
2.15 p.m. to S.15 P.M. . 
1 . ( 
1-84 
1-85 
1-97 
2-34 
1-86 
1-60 
8.50 p.m. to 8.50 a.m. . 
8.50 a.m. to 3.0 p.m. 
} 3 » - ! 
1-29 
1-52 
2-02 
2-12 
4.0 P.M. to 7.30 p.m. 
7.30 p.m. to 9.30 a.m. . 
} - { 
7-30 
3-60 
1-44 
1-26 
10.15 a.m. to 2.15 p.m. . 
2-15 p.m. to (3.15 p.m. . 
} * { 
2-89 
3-56 
2-42 
2-60 
7.0 p.m. to 9.30 p.m. 
9.30 p.m. to 8.15 a.m. . 
} « { 
6-70 
0-21 
1-S4 
1-68 
1 Loc. cit. 2 Journ. Physiol., Cambridge and London, 1890, vol. xx. p. 364. 
:: Schmidt, urea, sodic chloride, and potassium nitrate, Ann. d. Pltys. u. Chem., 
Leipzig, 1861, Bd. cxiv. S. 391. 
4 Schmidt, loc. cit., gum and albumin through ox-pericardium ; Hoppe-Seyler, Virchow's 
Archvo, 1856, Bd. ix. S. 245, blood-serum through ureter; Runeberg, loc. cit., gut, 
ureter, and pleural membrane, with serum, ascitic, and pleuritic fluids ; Gottwalt, loc. cit., 
egg albumin, hydrocele fluid, serum, and parovarian cyst fluid through ureter. 
5 Loc. cit. " i; Ztschr. f. physiol. Chem., Strassburg, 1882, Bd. vi. S. 508. 
