membranes. My studies led to the conclusion that the sieving properties of a given membrane were dependent on the blood flow rate, wall shear rate, and protein concentration polarization at the blood-membrane interface. Lee spent an entire afternoon with me, analyzing the data and discussing the content of my research with humility and comprehension, treating me as his peer ( Fig. 1 ). We event...

The classical Gibbs-Donnan equilibrium describes excess osmotic pressure associated with confined colloidal charges embedded in an electrolyte solution. In this work, we extend this approach to describe the influence of multivalent ion binding on the equilibrium force acting on a charged rod translocating between two compartments, thereby mimicking ionic effects on force balance during in vitro...

Although Frederick George Donnan (Fig. 1) grew up in Northern Ireland, actually he was born in Columbo, Ceylon (now Sri Lanka), on September 5, 1870 (1). He lost the sight of his left eye at the age of nine but did not allow this accident to handicap him. As a schoolboy, his main interest was in mathematics and physical science. He attended the Belfast Royal Academy from 1880 to 1889; and altho...

An answer has been given by Hitchcock 1 to a recent criticism by myself 2 of an argument vigorously exploited by Loeb in favor of his theory of colloidal behavior. Hitchcock suggests that this criticism rests upon a misunderstanding, but he admits the validity of my main contentions, and I am happy to note that Loeb has taken heed of them in two recent papers. I have no quarrel with many of the...

The presence of negatively charged, impermeant proteins in the plasma space alters the distribution of diffusible ions in the plasma and interstitial fluid (ISF) compartments to preserve electroneutrality. We have derived a new mathematical model to define the quantitative interrelationship between the Gibbs-Donnan equilibrium, the osmolality of body fluid compartments, and the plasma water Na+...

1. Colloids have been divided into two groups according to the ease with which their solutions or suspensions are precipitated by electrolytes. One group (hydrophilic colloids), e.g., solutions of gelatin or crystalline egg albumin in water, requires high concentrations of electrolytes for this purpose, while the other group (hydrophobic colloids) requires low concentrations. In the latter grou...