540 IMMUNOLOGY 



Stewart (1925) state that "the local cutaneous allergic reaction 

 in animals sensitized with dead bacilli varies in no way from that 

 in infected animals." 



3. Rich and McCordock cite the statement of Calmette (1927) 

 to the effect that in immunizing with B.C.G. allergy may disap- 

 pear for a while although acquired immunity persists. 



4. They cite the experiments of Willis who found that animals 

 immunized with a tubercle bacillus of low virulence developed 

 tuberculin allergy but retained it for less than two and one-half 

 years. After allergy had disappeared the animals were found to 

 ]iossess a pronounced degree of immunity when reinfected with 

 virulent organisms. 



5. In certain types of clinical cases of tuberculosis the admin- 

 istration of repeated and increasing doses of tuberculin results 

 in both a disappearance of allergy and a beneficial effect upon 

 the disease. This is especially true in certain types of skin and 

 also ocular tuberculosis. They cite the observations of Hamman 

 and Wolman that in a majority of cases treated with tuberculin 

 a change for the better is associated with an increased tolerance 

 of tuberculin. 



6. In regard to the assumption that allergic inflammation stimu- 

 lates fibrosis and the encapsulation of a tubercle, they call atten- 

 tion to the fact that connective tissue repair is a nonspecific 

 process and, according to MacCallum, is in no sense a part of in- 

 flammation and may not necessarily follow a violent inflammation. 

 That acute inflammation is not necessary for connective tissue 

 repair is evident to anyone who studies the organization of a 

 thrombus. 



7. They call attention to the fact that the tubercle bacillus has 

 little power to cause necrosis in the unsensitized body. After 

 tuberculin allergy develops, it takes but a minute amount of 

 tuberculin to produce extensive necrosis of tissue. In their 

 opinion the killing of tissue within the body cannot be regarded 

 as a defensive process. 



8. The authors believe that in reinfection the mechanism of im- 

 munity operates to destroy the tubercle bacillus before the allergic 

 reaction begins. 



Effect of Administering Vaccine Intravenously. — Additional 

 evidence which seems to support the theory of Rich and his col- 



