Toxic Products 



375 



reaction or by death, according to the extent of the dis- 

 ease and size of the dose administered. 



Preparation of Tuberculin. The preparation of tuber- 

 culin is simple. Flasks (Fig. 112) made broad at the bottom 

 so as to expose a considerable surface of the contained liquid 



Fig. 112. Massive culture of the tubercle bacillus upon the surface of 

 glycerin bouillon, used in the manufacture of tuberculin. 



are filled to a depth of about 2 cm. with bouillon contain- 

 ing 4-6 per cent, of glycerin and preferably made with veal 

 instead of beef -infusion. They are inoculated with pure cul- 

 tures of the tubercle bacillus, care being taken that the bacil- 

 lary mass floats upon the surface, and are kept in an incubator 



