298 BACTERIOLOGY. 



tralize the effect of tuberculin when injected into tuber- 

 culous guinea-pigs; but this test is insufficient and prob- 

 ably valueless, since tuberculin is not the same as the 

 unaltered products of the tubercle bacillus. Moreover, 

 it has been shown by Trudeau and Baldwin that other 

 substances which have no specific properties whatever 

 will have much the same effect as the serum under 

 certain conditions. Some make the further claim that 

 guinea-pigs injected with serum acquire an immunity 

 to the virulent tubercle bacilli, and that those already 

 infected live longer than the controls which receive no 

 serum; and some even claim to be able to cure animals 

 eighteen days after inoculation with, a culture of tu- 

 bercle bacilli. Very few observers, however, have suc- 

 ceeded in obtaining appreciable results with the serums 

 prepared by other experimenters. In spite of such con- 

 flicting testimony, it is probably safe to assert that no 

 serums now obtainable have any great value. Nor as 

 we look at the progressive nature of tuberculosis can 

 we see much ground to hope for the abundant de- 

 velopment of curative substances in the blood of ani- 

 mals. 



Prophylaxis. Meanwhile all energies should be 

 directed to the prevention of tuberculosis, not only 

 by the enforcement of proper sanitary regulations as 

 regards the care of sputum, milk, meat, disinfection, 

 etc., but also by continued experimental work and by 

 the establishment of free consumptive hospitals, and 

 by efforts to improve the character of the food, dwell- 

 ings, and condition of the people in general, we should 

 endeavor to build up the individual resistance to the 

 disease. It may be years yet before the public are 

 sufficiently educated to co-operate with the sanitary 



