MANUFACTURE OF VACCINES 739 



BUBONIC PLAGUE. Practically the same methods of procedure 

 have been followed in the experimental vaccination against bubonic 

 plague as in the case of Asiatic cholera. Cultures of the plague bacillus, 

 killed by heating at a temperature of 60 for one hour, have been used 

 with success. 



SENSITIZED VACCINE 



Besredka* has developed modified bacterial vaccines known as 

 sensitized vaccines. In the preparation of these the living micro- 

 organisms are brought into contact with the homologous antisera 

 and the mixtures allowed to stand for approximately twenty-four hours 

 at room temperature. The organisms are then removed by centrifugal- 

 ization, washed and placed in suspension. The remaining processes 

 of manufacture are similar to those employed in the preparation of 

 ordinary bacterial vaccines. 



Besredka and his associates explain the advantage of sensitized 

 vaccines by the fact that in such preparations the microorganisms, by 

 reason of having been in contact with homologous antisera, are 

 sensitized with specific amboceptors. Therefore, the sensitized organ- 

 isms are capable of immediately combining with complement, when 

 introduced in the blood of the patient, and prompt immunization should 

 follow. 



Both living and killed sensitized microorganisms have been used 

 experimentally, Besredka f having advocated the use of the former as 

 devoid of harmful properties and more certain of successful results. 

 Sensitized vaccines are still in the experimental stage, and their ad- 

 vantage over the ordinary bacterial vaccines is at present a debated 

 question. 



TOXIN ANTITOXIN MIXTURE. 



Babes, J in 1895, first suggested the use of diphtheria toxin and antitoxin mixture 

 as a method of immunization against diphtheria. Through the work of Park and 

 Zingher|| and others who preceded, this method is being adopted in practice, 

 especially as a means of prophylaxis against diphtheria in schools and hospitals. 

 The mixture consists of active diphtheria toxin and antidiphtheritic serum in the 

 proportion of 80 per cent, of the L + dose of toxin to one unit of antitoxin. 



* Besredka, Compt. Rend, de 1'Acad. Sci., 1902, 134, p. 1330. 

 t Besredka, Bull, de I'lnst., Pasfeur, 1910, 8, p. 241. 

 J Babes, Bui. Acad. de Med., Paris, 1895. 34, p. 216. 

 || Park and Zingher, Jour. A.M. A. 1915, 65, p. 2214. 



