SIGNIFICANCE OF PHENOMENON 357 



extract of B. tyjjiiosus ^\'l^ch was prepared in a niaiiner similar 

 to tuhermlin. WHien typhoicliii was applied to the abraded skin 

 ol the torearni a high j)ercentage oi positi\e tests \vas obtained 

 in individuals who had been vaccinated against typhoid lever one 

 month to five years pre\'ioiisly. The reaction consisted of an area 

 of redness and swelling ^vhich reached its maximum intensity in 

 about t^venty-four hours. 



Bessau (iQi^)) demonstrated the production of tuberculin hy- 

 persensitiveness with heat-killed B. tuberculosis. The best sensi- 

 tixity was obtained after t^vo to three weeks of injection of the 

 bacilli intraperitoneally. Zinsser and Petroflf (1924) made exten- 

 sive studies on the elicitation of tuberculin hypersensitiveness by 

 means of dead tubercle bacilli. They found that Avhen large 

 doses were injected the hypersensitiveness appeared as rapidly as 

 with living bacilli. The extent of local reaction to the injected 

 dead tubercle bacilli and the degree of hypersensitiveness sho^ved 

 a parallelism. Boiling of tubercle bacilli to 100° c. did not de- 

 stroy the property. The reactions ^vere comparable in intensity 

 to those in tuberculous animals. The results of sensitization with 

 the extracts of B. tuberculosis prepared by means of differ- 

 ent methods, as well as culture filtrates, gave no clear-cut tuber- 

 culin hypersensitiveness. Tytler (1930) failed to produce sensi- 

 tivity ^vith fjacillary protein in solution but there Avere obtained 

 strong skin reactions in a few animals injected with a dry protein 

 incorporated in beeswax to give slow, continued absorption. Mac- 

 kenzie and Woo (1925) found that repeated intracutaneous in- 

 jections of guinea pigs for several weeks with an alkaline extract 

 of pneumococcus produced in about tAvo-thirds of the animals an 

 allergy with the skin reaction similar to the allergic response of 

 tuberculosis. Mcjunkin (1921) injected living ttdjercle bacilli in- 

 traperitoneally in tubercidous guinea pigs causing a fatal reaction 

 and injected the peritoneal exudate after filtration subcutaneously 

 into normal guinea pigs. The latter guinea pigs gave character- 

 istic intracutaneous reactions occasionally necrotic after eight to 

 ten days, the sensitivity disappearing after one to four ^veeks. 

 Many authors (Mcjimkin, 1921; Paraf; Zinsser and Tamiya, 1926; 

 Caspari; Lange and Freund, 1926; and others) , suggest that the 

 sensitizing power of the exudates and extracts depends on the oc- 

 currence of an inflammatory reaction specific or non-specific, and 

 that the bacillary protein either injected or derived from the 



