Abstract
In the course of experiments on denaturation of serum∗ I observed the phenomenon of gelation of human sera following the addition of ethyl alcohol in higher concentrations. Gate and Papa-costas 1 described a similar serological reaction using formaldehyde. They offered this as a test for the diagnosis of syphilis but subsequently it was found to be of no value as such.
Principle of method: A known amount of ethyl alcohol (80%) is added to an equal amount of serum, shaken well, and the time determined in which the mixture turns into a gel. The gelation may at times be so complete that the tube may be inverted without the contents being spilled. The test-tubes used for the reaction must be of equal diameters when comparative studies are made.
Method: 0.2 cc of serum are measured into test-tubes 8 cm long, 7.5 mm internal diameter. Over the serum is then stratified 0.2 cc 80% ethyl alcohol. At the adjacent surfaces of these fluids a precipitate is formed. The tubes are then well corked and, shaken vigorously until the mixing of the serum and alcohol is complete. This is recognizable by the milky white to yellowish white appearance which the solution assumes. The results are designated according to the degree of gelation which has taken place as follows: +++, complete; ++(+), almost complete; ++, strong; +(+), medium; +, weak; (+) beginning; —, none.
The test is carried out at room temperature. After 5 min., 30 min. and 3 hours the results are read; each tube is taken from the test-tube stand and is slowly tilted between thumb and forefinger at first to an angle of almost 90° and then, if the gelation is strong to complete, to an angle of 180°. While the conditions of this experiments are very simple, the differences in the intensity of gelation are very striking. In time the mixture coagulates to such a degree that one single large flocule is formed.
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