Abstract
The theory and construction of a dynamic osmometer suitable for 0.5 ml. of fluid is descr. and also a new method for making thin collodion membranes of high permeability to the solvent but completely impermeable to beta-lactoglobulins. Results are reported for unbuffered solns. of beta-lactoglobulin. These showed a marked degree of non-ideality. A value of 37,000 [plus or minus] 540 was obtained for the molecular wt.