Abstract
The accuracy of the determination of the blood group depends essentially upon the sterility of the typing serums and the freedom from formation of precipitates. The usual method of preserving stock typing serums is in a liquid form with the addition of 0.5% phenol. Lattes 1 has shown that serums preserved with phenol as well as many other preservatives, become turbid and form precipitates, and advises the use of sterile serums. The length of time that these aseptically collected serums will remain uncontaminated is variable and indefinite. Prati, 2 Grove and Crum 3 have demonstrated that liquid typing serums are very subject to contamination by a mustard bacillus and thus develop in the contaminated serums a non-specific property of human blood cell agglutination.
Desiccation may offer a desirable means of preservation. The value of desiccation is dependent upon its effect in time on the agglutinins in the serums. Slides were prepared as follows: Near the end of the slide was placed 0.01 cc. of type II serum, according to the Moss classification, containing 0.5% phenol and allowed to dry as a drop in the open air. Similarly near the other end of the slide 0.01 cc. of type III serum containing 0.5% phenol was placed. Each serum was marked below the drop to identify its group. The slides were divided into 2 lots, one lot being held at room temperature and the other at 8°C. Liquid phenolized typing serums were prepared at the same time for controls. These were tested at intervals.
Rosenthal 4 demonstrated that typing serums could be preserved in a liquid form by staining and that they required no particular aseptic precautions in handling and storing.
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