Abstract
A report was made about a year ago describing a simple, inexpensive method for concentrating serum under sterile conditions in sterile, cellophane sausage casings. 1 Subsequently, Dr. P. A. Kober 2 informed me that he had described this process in 1917 and 1918 under the name “Pervaporation” .
The casing filled with serum is suspended by the tied end from a hook either at room temperature or in a large mechanical refrigerator kept at 5°C, the bag being placed in front of an electric fan. The serum can be concentrated to one-third its volume in about 48 hours at room temperature, and after a somewhat longer interval in a refrigerator. We have also concentrated ascites fluid by this method to as much as one-tenth its original volume. The concentrated serum or ascites fluid is then passed through a Buchner paper pulp filter, and subsequently, a Berkefeld filter. It is then put into sterile vials, and tested for its sterility.
By this method of concentration only moisture and gases are removed; all other substances, including salts, and non-protein nitrogenous materials are concentrated to the same degree as the protein.
It seemed advisable to have available, if possible, a simple method whereby protein constituents could be concentrated with most of the salts and non-protein nitrogenous materials removed, since in conditions such as nephrosis it is manifestly undesirable to inject large amounts of salts or non-protein nitrogenous substances.
The problem of concentrating serum and at the same time dialyzing out most of the salts was solved by immersing the bag of serum in a very pure, inexpensive, colorless commercial corn syrup.∗ It was found that the serum concentrated more rapidly by this technic than by the air method, and that, at the same time, a great deal of sodium chloride and non-protein nitrogenous materials dialyzed out.
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