548 IMMUNOLOGY 



negative tests. In their opinion the primarily infected children 

 offer a double liability in that many of them continue to harbor 

 virulent organisms and all of them are allergic. When reinfec- 

 tion occurs the organisms are implanted in allergic tissue. The 

 resulting reaction leads to destructive and progressive changes. 

 Casperis, in discussing the work of Myers and Harrington, sug- 

 gests that the children who show positive tuberculin tests on first 

 examination constitute a group that has greater exposure to 

 tuberculosis than the negative reactors and therefore, it might 

 be expected that more of this group would develop the reinfec- 

 tion type of tuberculosis as a result of i-epeated exposure. Myers 

 states, however, that in his series, contact was broken so far 

 as possible immediately after the skin tests were done. It is 

 difficult to compare these results with the animal experiments of 

 Lurie since the primary infection in the rabbits was with the 

 human type of tubercle bacillus which does not produce progres- 

 sive tuberculosis in rabbits and hence there is no danger of adult 

 tuberculosis arising from the flaring up of old primary foci such 

 as may occur in children. The evidence at hand seems to show 

 that mild ]>rimary tuberculosis confers a relative immunity «is 

 well as definite allergy upon an individual; that excessive ex- 

 posure to virulent tubercle bacilli nuiy break down this inuuTUiity; 

 and that in such cases the allergic inflammation helps in that it 

 assists in mobilizing phagocytic cells but is detrimental in that it 

 plays a definite role in necrosis, extension of the inflammatory 

 processes and general systemic reactions. 



Different Opinions as to B.C.G. Vaccination. — For a great many 

 years there has l^een a spirited debate over the question of active 

 immunization against tuberculosis. There are at least four dis- 

 tinct views being presented at the present time. One group would 

 not immunize at all but would depend entirely upon measures 

 designed to prevent first infection ; a second group would su})ple- 

 ment such measures by immunizing all tuberculin-negative chil- 

 dren with a killed vaccine; the third group would substitute 

 B.C.G. for the killed vaccine; while the fourth group feels that 

 vaccination should be viewed experimentally for fifteen or twenty 

 >ears before it is generally adopted or rejected. 



Those who would not immunize at all state that in their opinion 

 immunization is at best a questionable practice, subsequent con- 



