CONTRIBUTION TO OUR KNOWLEDGE OF TUBERCULOSIS ANTITOXIN.

In a paper on this subject, published in 1897, I reported on a series of experiments, which, although not altogether uniform in their results, certainly established the existence of a substance with a pronounced affinity for the toxin of the tubercle bacillus. To the experienced and well-versed reader this was nothing new; antitoxic properties of the serum of animals treated with tubercle bacilli or their metabolic products had before been observed and described repeatedly, the whole question being only sidetracked by the very natural desire to employ this quality practically. The inadequacy of the antitoxic intensity for therapeutic purposes led to a doubt of its existence, and up to this day this consideration of practical possibilities has dominated the subject. It is not my aim to here enter into a discussion of the startlingly prolific literature on antituberculous serum. A surprisingly large percentage of it exhibits an utter ignorance of