HYPERSENSITIVENESS 521 



of Ihiit scliool year. This constituted an attack rate of 44.5 per 

 cent which was sixteen times the annual rate noted for the first 

 three years of the course. They say that this rate of 44.5 per cent 

 is fifty-six times the infection attack rate they found for children 

 in the city schools who resided in private homes. Stewart and his 

 associates also report high attack rates in private hospitals, es- 

 l)ecially those that maintain wards for tuberculous patients. 



Significance of Skin Reaction in Children. — Stewart (1934) has 

 published an interesting paper on the skin sensitiveness to tuber- 

 culin in primary tuberculosis. He reports the results of extensive 

 roentgenologic and clinical investigations of 188 children ranging 

 in age from 8 to 171/) years who gave positive skin reactions to 

 the intracutaneous administration of 0.1 mg. of old tuberculin. 

 In 132 children of this group he found either characteristic cal- 

 cified hilus glands or Ghon tubercles or both, twenty-one showed 

 slight or questionable calcification of hilus glands, eight showed 

 only pleural thickenings and twenty-one showed negative chest 

 plates. He states that clinically the entire group showed no symp- 

 toms of tuberculosis and could be distinguished from normal unin- 

 fected children only by means of the tuberculin test and roentgen 

 examinations. 



Tuberculin Surveys With PPD. — Long, Aronson and Seibert 

 (1934) report on results obtained in tuberculin surveys with the 

 purified protein derivative and a highly potent OT, i-espectively. 

 This woi-k was done, apparentlj^ with an idea of determining the 

 potency, uniformity, and general reliability of the new tuberculin, 

 Tlie results of their work may be partly summarized as follows : 



1. They found that an initial dose of 0.00002 mg. of the purified 

 protein derivative detects a high percentage of total positive re- 

 actors to OT with very few severe reactions. The remaining posi- 

 tive reactors to 0.01 mg. and 1.0 mg. of highly potent OT are 

 detected by a dose of 0.005 mg. of PPU. 



2. They recommend that PPD be incorporated into sterile lac- 

 tose tablets in quantities of 0.0002 mg. and 0.05 mg. per tablet 

 for convenience in the preparation of ten first or second doses 

 to be used in tuberculin tests. 



Park, Kereszturi, Mishulow (1933) also point out the superiority 

 of the tuberculin test over the x-ray as an aid in the diagnosis of 



