1893.] NATURAL SCIENCES OF PHILADELPHIA. 101 



presence of an excess of glycerin and in a temperature of 40° C.,. 

 become branched. The young bacilli, when introduced into the 

 animal tissues, produce tuberculosis, while the older cultures grad- 

 ually lose their virulence, in all probability owing to their inability 

 to reproduce themselves. This fact indicates that the branched 

 form represents an involution life-cycle of the germ. Notwith- 

 standing the fact, however, that the devitalized, dying or dead ba- 

 cilli cannot produce consumption, they, with their products, effect a 

 decided increase in tubercular inflammation, which inflammatory 

 process even results in necrosis of the tissues. These phenomena 

 led to investigations proving the correctness of the hypothesis first 

 published in my Monograph on Immunity (Medical News of Oct. 

 19, 1889) to wit : " It is possible that, by a thorough filtering out of 

 bacilli from tuberculous material, a filtrate might be obtained and 

 attenuated so that by systematic inoculations a change might be 

 produced on living tissues that would enable them to resist viru- 

 lent tubercle bacilli. In this line of experimentation I proved 

 that the presence of the germs was not necessary to produce the 

 hyper-inflammatory condition of the tuberculous tissue but that it 

 was a product of the bacillus that caused the reaction upon the 

 tuberculous animal tissues. |This, since called Tuberculin and 

 introduced into the human economy for the purpose of curing 

 tuberculosis when introduced into animals suffering with artifi- 

 cially produced tuberculosis, often destroyed the condition called 

 consumption and in many cases appeared to produce immunity to 

 the poison of tuberculosis." The process, however, was not quite 

 so successful in animals which had contracted tuberculosis through, 

 one of the natural channels. In these cases, tissues surrounding 

 that which was recognized as tuberculous afterward became infected 

 with consumption. While this was and still is discouraging we 

 have good reason to believe that Tuberculin will be permanently 

 established as a remedy for this pathological condition. The toxic 

 albumose causing inflammation of tissues markedly tuberculous, 

 coupled with the fact that it is found in such tissues, led me to inquire 

 whether or not some other constituents of animal tissues, patho- 

 logical or normal, would produce reaction if introduced in excess 

 into the general circulation. This line of experimentation was 

 begun by first using an albumose of the goat, a comparatively 

 immune animal. This material, however, if at all active as a 

 remedial agent in tuberculosis, is so slow in its effects that I have 



