ACTIVE IMMUNIZATION FOR THERAPEUTIC PURPOSES 203 



The general idea is to make an emulsion at the start that is stronger 

 than the one desired in the end, and subsequently to dilute this to 

 the required degree. The emulsion is transferred from the last tube to 

 a sterile test-tube, care being taken that the fluid does not come in 

 contact with the neck of the tube, as otherwise some organisms may 

 dry here and subsequently escape sterilization. This is then carried 

 out in a water-bath at a temperature of from 60 to 65 C. An 

 exposure of one hour is sufficient, counting from the time that 

 the contents of the tube reach the desired point. A number of 

 sterile glass beads are now added, and the tube, tightly closed with a 

 sterile stopper, shaken by hand or with a machine for about fifteen 

 to twenty minutes. The bacterial content is then ascertained, as 

 described above (see Preparation of Typhoid Vaccine, p. 190). As 

 diluent I use an 0.5 per cent, solution of carbolic acid, taking care 

 that the final content of the latter, in the finished vaccine, does 

 not fall below 0.25 per cent. The tube is then allowed to stand on 

 end overnight (so as to test the sterility of that portion of the tube), 

 and a culture made the next day, using a good-sized drop for each 

 tube, which is conveniently placed in broth or milk. The preparation 

 is finally provided with a label, giving the name of the organism, 

 and the titer of the vaccine per 1 c.c. If desired, the vaccine can, 

 of course, also be put up in glass beads or ampules, each containing 

 a single dose of 1 c.c. In this form the material is usually furnished 

 by the dealers. 



While the common bacterial vaccines may be prepared in the 

 clinical laboratory from autogenous material, this is out of the 

 question in the case of the tubercle bacillus. Such a vaccine is best 

 obtained from the dealers, and is sold under the name of Koch's 

 Neu (new) Tuberculin, bacillary emulsion). It is prepared by care- 

 fully grinding fresh cultures of the bacillus, after being dried in the 

 vacuum, in an agate mortar, or in a specially constructed mill, when 

 the organisms are emulsified in equal parts of water and 50 per cent, 

 glycerin (100 parts of each for one part of bacilli). 1 c.c. of this 

 preparation contains 5 mgrms. of bacilli, and from it the required 

 dilutions are made, care being taken to sterilize the stock solution 

 before diluting, by exposure to a temperature of 60 C. for one hour. 

 As diluent a 0.25 per cent, solution of lysol in physiological salt 

 solution is used. 



