BACILLUS PEST IS 399 



though they be attenuated to the point of harmlessness, 

 as decided by animal tests, is more than likely to operate 

 against the routine employment of such cultures in the 

 protection of human beings by vaccination. 



Besredka, of the Pasteur Institute, 1 advocates the use 

 of a "sensitized vaccine" against plague. This consists of 

 dead pest bacilli (killed by heat) that have been mixed with 

 antiplague immune serum obtained from an artificially 

 immunized animal. It is claimed by him that the process 

 of sensitizing lessens the toxic action of the dead bacteria; 

 diminishes the risk run by injecting them and eliminates 

 the uncomfortable local and constitutional reactions that 

 so often accompany the injections; while at the same time 

 the protective properties of the "vaccine" are preserved. 

 Rowland, 2 in a critical review of the subject, fails to find 

 any neutralization of the toxic properties of the dead bacteria 

 through sensitization, but states that Besredka's "vaccine" 

 possesses good immunizing power and users of it have 

 reported favorably as to the minimum of discomfort fol- 

 lowing its inoculation. The principle here used has been 

 applied by Besredka, Gay and others to the making of pro- 

 tective agents for other types of infection. 



Antiplague Serum. The general principles that are 

 involved in the induction of immunity with antibody 

 formation hold for plague as for a number of other types 

 of infection; that is to say, the repeated injection into sus- 

 ceptible animals of non-fatal doses of the specific organism 

 or the products of its growth and disintegration, results in the 

 elaboration in the injected animal of substances that are in 

 one way or another antidotal, destructive or neutralizing for 

 the matters injecteoT. 



1 Bull, de 1'Institute Pasteur, 1910, viii, p. 241 ; 1912, x, p. 529. 



2 Journal of Hygiene, Plague Supplement II, 1912, p. 344. 



