When one delves into the vast amount of bewildering literature that represents the present day knowledge of tuberculins, one is apt to emerge with a chaotic idea, if any at all, of the entire matter. From this literature I have made selections, and have arranged the matter in the way in which it makes the subject clearest to me. I present it here as it applies to diagnostic tests.
Before taking up the subject matter I will give some definitions of terms used, in accordance with my plan:
—A substance found in the blood and tissues (Ludke, 1907) of a tuberculous person after being treated with tuberculin. In this connection this would also be called substance sensabilitrice, antibody or amboceptor.
—The exciting agent—in this case, the injected or applied tuberculin.
—A protective substance found in normal blood serum. Its union with the foregoing factors has been found
RYAN LM. TUBERCULIN AS A DIAGNOSTIC TEST OF TUBERCULOSIS IN MAN. JAMA. 1918;70(14):982–985. doi:10.1001/jama.1918.02600140014007