1903.] Immunising Effects of Contents of Typhoid Bacillus. 351 



*' Upon the Immunising Effects of the Intracellular Contents of 

 the Typhoid Bacillus as obtained by the Disintegration of 

 the Organism at the Temperature of Liquid Air." By Allan 

 Macfadyen, M.D. Communicated by Lord Lister, O.M., 

 F.E.S. deceived February 19 — Bead March 12, 1903. 



In a previous communication* it was shown that it was possible 

 to disintegrate mechanically the typhoid bacillus at the temperature 

 of liquid air, and to obtain the cell-juices of the organism. 



The typhoid cell-juices obtained by this method on inoculation into 

 animals proved toxic or fatal. It was, therefore, concluded that the 

 typhoid bacillus contained within itself an intracellular toxin. 



It remained to test the typhoid cell-juices for immuninising and 

 other properties. The preliminary experiments in this direction, 

 which form the subject of the present note, were made upon the 

 monkey. The monkey was selected as an animal most likely to 

 furnish data of possible application to man. For this purpose the 

 typhoid cell-juice was administered subcutaneously to the monkey. 

 The injections did not produce any general symptoms beyond a 

 transient rise in temperature, whilst the material was quickly 

 absorbed after each injection without any traceable local effect. In 

 this manner doses of 0*5 to 1 c.c. of the material were injected at 

 intervals. An immediate result was the agglutination of the typhoid 

 bacillus by the serum of the blood of the treated monkeys, whereas no 

 such effect was produced by the serum of monkeys which had not been 

 treated. This furnished useful evidence that the animals were under 

 the influence of cell-juices derived from the typhoid organism. The 

 injections were repeated at intervals of three to four days, and after a 

 lapse of four to six weeks the animals were bled. The serum obtained 

 was then tested for immunising properties. The test objects were 

 (1) a virulent culture of the typhoid bacillus, and (2) the intracellular 

 toxic juice of the same organism. A varying amount of the virulent 

 bacilli and of their toxic cell-juice was mixed with a varying quantity 

 of the serum. The respective mixtures were then injected into the 

 peritoneal cavity of the guinea-pig. 



The broth cultures of the typhoid organism used in the experiments 

 were per se lethal in doses of 0*1 c.c. in five to ten hours. The typhoid 

 cell-juices were fatal in doses of 0*2 and 0*1 c.c. in three to five hours, 

 and in doses of 0'05 c.c. in about twelve hours. The serum was thus 

 tested for (1) specific antibacterial and (2) specific antitoxic properties. 



The experiments showed that the serum of the monkey, after injec- 

 tions of the typhoid cell-juices, possessed antibacterial and antitoxic 



* ' Hoy. Soc. Proc.,' supra, p. 76. 



