TUBERCULOSIS. 237 perimental studies of Trudeau and Baldwin, however, antiphthisin is only much diluted tuberculin, and exerts no demonstrable influence upon the tubercle bacillus in vitro, does not cure tuberculosis in guinea-pigs, and probably inhibits the growth of the tubercle bacillus upon culture-media to1 which it has been added, only by its acid reaction. On the other hand, Ambler has used antiphthisin with excellent results in the treatment of human tubercu- losis. Numerous experimenters, prominent among whom are Tizzoni, Cattani, Bernheim, and Paquin, have experi- mented with the tubercle bacillus and tuberculin, hoping that the principles of serum-therapy might be applicable to the disease. Nothing positive has, however, been achieved. The first-named observers claim to have im- munized guinea-pigs, in whose blood an antitoxin formed; the last-named thinks the serum of immunized horses a specific for tuberculosis. The field of experimentation is an inviting one, though the chronic course of the dis- ease lessens the certainty with which the results can be estimated. Babes and Proca, in an experimental research upon the action of the antituberculous serum, claim for it a decided specific action, and demonstrate experimentally that ani- mals inoculated with tubercle bacilli and injected with the serum are protected from the spread of the disease. Mafucci and diVestra found that by injecting guinea- pigs with serum from sheep immtinized by injections first of dead, then of living cultures of tubercli bacilli, although no cures were brought about, the vitality of the animals was maintained longer. Unprotected animals died in fifty to fifty-three days. Those injected after in- fection, seventy-four days, and those injected before infec- tion, ninety-one days. The author1 made an elaborate study of the so-called antituberculin, suggested by Viquerat, and widely praised 1 Jour, of the Amer. Med. Assoc., Aug. 21, 1897.