﻿XV. PLAGUE VACCINATION IN HUMAN BEINGS. 



It having been conclusively demonstrated by animal experiments that 

 by the method of vaccination against plague a much greater immunity 

 could be produced than by any other method of inoculation, and earlier 

 experiments 126 having demonstrated the entire safety of the inoculation 

 of human beings with large amounts of the strain "Pest A virulent," more 

 extensive vaccinations were made in man with this culture. The size 

 of the dose employed for an adult was always one 24-hour agar slant 

 culture and for children from one-third to one-half this quantity. Sur- 

 prising as it may seem, the injection of these large amounts of the 

 living plague organism have not given rise to any very severe reactions. 

 A few hours after the inoculation, the temperature of the individual 

 usually begins to rise. When the injections have been made in the 

 morning, the fever may in the evening of the first day reach from 38.5° 

 to 39° C. Only in a few cases has it touched 40°. The temperature 

 gradually declines on the following day and by the third of fourth one, 

 has become normal. Occasionally, the cases showed a moderate leuco- 

 cytosis after the injection. As in the earlier experiments, the organisms 

 were always suspended in 1 cubic centimeter of 0.085 saline solution and 

 the inoculations were made deeply into the deltoid muscle. Intramuscular 

 instead of subcutaneous injections were performed on account of the 

 quicker absorption which occurs from the former method, and because 

 Meltzer and Auer 12T found that intramuscular injections as regards 

 absorption in general stand in value very near that of a direct injection 

 into the circulation. On the day after the vaccination there is usually 

 distinct induration and redness about the point of the injection with some 

 soreness on pressure, but these symptoms subside in from one to three 

 days. No visible suppuration of the tissues has ever occurred. 



In order to observe the length of time during which the organisms 

 remained alive in the tissues, as mentioned, similar inoculations were made 

 in monkeys and the tissues near the point of injection incised at var}dng 

 intervals after the vaccination, and microscopical preparations and 

 cultures made from the drops of blood which escaped from the wound. 

 The technique employed was the same as that used in the experiments 

 relating to increasing the virulence of the plague organism, as described 

 on page 301. In the different series of cultures made from the animals 



^TMs Journal (1900), I, 181. 

 ™Jour. Exp. Med. (1905), 7, 77. 

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