BACILLUS OF TUBERCULOSIS. 297 



of producing violent reactionary symptoms, and the 

 graded increase of the subsequent doses within such 

 quantities as are known never to produce reaction in 

 healthy individuals, would seem to afford the best 

 protection against unpleasant results and misleading 

 evidence. " 



Antituberculous Serum. Whether serum-therapy is 

 destined to solve the problem of the treatment of tuber- 

 culosis remains for the future to decide, but up to the 

 present the results obtained with antituberculous serum 

 do not warrant our forming such an opinion. The at- 

 tempts to obtain from animals chiefly horses a serum 

 which would be protective have been carried out along 

 very much the same lines as Koch's experiments upon 

 man. The methods adopted have been as follows: Old 

 cultures of tubercle bacilli grown in 5 per cent, glycerin 

 bouillon have been filtered either with or without pre- 

 vious boiling, and then injected into animals, this 

 process being similar to Koch's with his first tuberculin. 

 Others have injected living virulent or non-virulent 

 tubercle bacilli, either alone or with their culture fluids; 

 others still (Biichner) have injected the bacterial proto- 

 plasm obtained by crushing tubercle bacilli together 

 with sand and squeezing them ; this, like Koch with 

 his new tuberculin, being an attempt to get from the 

 unaltered products and cell-contents of the bacilli the 

 formation in the body of bactericidal or immunizing 

 substances. 



Among the many claiming good results in man or 

 animals thus treated may be mentioned Hericourt, 

 Bichet, Bernheim, Maragliano, Yiquerat, Paquin, 

 de Schweinitz and Dorset, McFarland, and others. 

 The majority claim for their serum the power to neu- 



