In the course of our studies on the tuberculin test and the Schick test,1 we found that certain nonspecific factors influenced the former, but had little effect on the latter. We were interested in studying the Dick test in the same manner.
The toxin used in this work was secured through the courtesy of Dr. George F. Dick and Dr. Gladys H. Dick. It was diluted 1: 1,000 with sterile 0.85 per cent sodium chloride solution within eight hours of its use. One tenth of a cubic centimeter of the diluted toxin was injected intracutaneously and the readings were made in from eighteen to twenty-four hours. At the beginning of the study, control tests were performed with diluted toxin which had been heated in a boiling water bath for an hour. Later the practice of performing control tests was discarded, as it was felt that they were unnecessary. The