464 BIOLOGY OF PNEUMOCOCCUS 



layed reaction ensued after a similar injection of pneumococcal 

 protein. The appearance of circulating antibodies for one or more 

 heterologous types in a group of patients repeatedly tested with 

 soluble specific substance was believed by the authors to be refer- 

 able to the antigenic action of the polysaccharide introduced into 

 the skin during successive tests. 



In opposition to the conception that skin reactivity to the cap- 

 sular polysaccharide of Pneumococcus is associated solely with 

 recovery from pneumonia are the results of Alston and Lowdon 

 (1933). 10 The majority of the individuals studied (63 per cent) 

 who had not recently suffered from pneumococcal infection reacted 

 positively to the intradermal injection of Type II polysaccharide, 

 the percentage of reactions increasing in the older age groups. Re- 

 tested five to twelve months later, 92 per cent of the subjects pre- 

 viously exhibiting a positive reaction were found to have retained 

 the ability to react to the same antigen. The capacity to respond 

 to similar injections decreased and in some cases entirely disap- 

 peared when the test injections were repeated at short intervals. 

 The authors also reported that a considerable number of normal 

 subjects, especially older persons, exhibited a delayed reaction in 

 addition to the immediate reaction or independent of it. 



The manifestation of both immediate and delayed reactions may 

 be explained by the fact that the introduction of pure pneumococ- 

 cal capsular polysaccharide into the skin of a positively reacting 

 subject is promptly followed by a local inflammatory condition, 

 while after the similar injection of the C Fraction or of somatic 

 protein, an interval elapses before any local reaction occurs. Skin 

 sensitivity to pneumococcal type-specific carbohydrates and the 

 presence of specific antibodies in the circulating blood were found 

 to exist independently of each other. The findings of Alston and 

 Lowdon agree with those reported in the previous year by Sutliff 

 and Finland, 1360 who reported that skin reactions to acetic acid- 

 precipitable protein and autolysates of Pneumococcus were nega- 



