For the control of diphtheria epidemics we now have a means which is practical, efficient, and available to any physician. Schick, working in von Pirquet's clinic in Vienna, discovered the value of this test, and therefore it is known as Schick's test. It requires no special technic that is not easily acquired by any physician.
The test depends on the reaction of nonimmunes to an injection of diphtheria toxin, the amount of which is a one-fiftieth minimum lethal dose for a 250 gm. guinea-pig. The necessary articles are a 1 c.c. hypodermic syringe graduated into tenths, a very fine needle, sterile normal salt solution, and the diphtheria toxin. The toxin is diluted in the salt solution according to the strength as determined by laboratory tests. The amount of the solution used will depend on the dilution. It will be found convenient to make the dilution so that approximately 0.2 c.c.