138 PHARMACEUTICAL BACTERIOLOGY. 



10. Tuberculins. 



The tuberculins are of special interest as they give great promise in the 

 successful treatment of tuberculosis. The different kinds have their special 

 use. Their manufacture is briefly outlined as follows: 



A. Tuberculin Old (T. O.). This is the original Koch tuberculin or 

 Koch lymph and is a concentrated bouillon culture of the tubercle bacillus, 

 which has been filtered to remove the germs. It is a toxin solution and 

 not a bacterin proper. 



B. Tuberculin Residuum (T. R.). This is prepared by grinding the 

 dried tubercle bacilli, extracting with water, centrifugalizing, discarding the 

 supernatant liquid, regrinding the sediment, which is first allowed to dry, 

 and mixing with glycerin and water. It is thus a suspension of pulverized 

 tubercle bacilli in an aqueous solution of glycerin. The grinding process 

 is tedious and requires much time. The tuberculin is standardized so that 

 i c.c. will represent 10 mg. of the dry culture. 



The supernatant liquid, after centrifugalizing, is sometimes drawn off, 

 instead of rejecting, and constitutes the upper tuberculin (T. O.) (Obere 

 Tuberculin). These two tuberculins (the T. R. and the T. O.) differ in 

 therapeutic value and in physical properties. 



C. Bacillus Emulsion (B. E.). This consists of pulverized tubercle 

 bacilli suspended in 50 per cent, glycerin and is standardized to contain 5 mg. 

 of solid matter per c.c. It differs from T. R. in that the supernatant liquid 

 (T. O.) is not drawn off. 



D. Tuberculin Precipitate (T. R.). This is obtained from old tuberculin 

 by precipitation with alcohol, drying and pulverizing the precipitate. It is 

 used in making the Calmette eye-test. (See tuberculosis.) 



E. Bouillon Filtrate (Tuberculin Filtrate B. F.Denys Tuberculin). 

 The tubercle bacillus cultures are passed through a Berkefeld filter to 

 remove all germs. The filtrate is preserved with trikresol. 



ii. Small-pox Vaccine. 



Small-pox vaccine is not a true toxin nor yet a true bacterin. Its value 

 in the eradication of small-pox has world-wide recognition. The following 

 is the manner in which small-pox vaccine is prepared. 



A. Selecting the Animal. A young heifer (five to ten months old) is 

 selected, tested for tuberculosis by means of tuberculin. The animal is 

 observed for a time to make sure of general condition of health ; is well fed 

 and well cared for, under conditions as sanitary as it is possible to keep them. 



B. Inoculating the Animal. The heifer is strapped securely to a frame- 

 work, back down, the udder region is cleansed, shaven and cross marked 

 (scarified) with a sharp scalpel. The cuts are just deep enough to cause the 



