620 BIOLOGY OF PNEUMOCOCCUS 



local effects following the introduction of pneumococcal antigens 

 into the skin should be more clearly defined and classified and all 

 interpretations should be based on such definition and classifica- 

 tion. 



The problems involved in the several kinds of reactions elicited, 

 their relation to the clinical course of infection, and their inter- 

 pretation in respect to preexisting or newly developing states of 

 hypersensitiveness and immunity are still to be studied and solved. 

 Recent studies of the somatic C polysaccharide suggest that cer- 

 tain forms of reactivity, both serological and cutaneous, are not 

 specific in an immunological sense, but are rather an expression of 

 chemical changes in the blood associated with the acute stage of 

 active infection. 



THE NATURE OF PNEUMOCOCCAL ANTIBODY 



The behavior of antibodies of immune serum in the presence of 

 protein precipitants and the molecular size of the immune sub- 

 stances as determined by ultracentrifugation and ultrafiltration 

 lead to the tentative assumption that these antibodies represent 

 modified forms of serum proteins, having in general the chemical 

 properties of globulins. The isolation by advanced methods of anti- 

 body or antibodies in purer form than that in which they have been 

 previously obtained promises to be a desirable point of departure 

 for further inquiry into the chemical nature of antibodies, the 

 elucidation of the mechanism of immunological reaction, and for 

 the development of a more efficient therapeutic serum. 



CONCENTRATION OF ANTIPNEUMOCOCCIC SERUM 



Methods for concentrating and refining antipneumococcic serum 

 have undergone notable improvement, but it cannot be claimed 

 that the agent approaches the perfection of diphtheria and teta- 

 nus antitoxin. Raw serum of greater potency is the first requisite, 

 and then there must be devised chemical procedures which will 

 make it possible to separate the desired antibody or antibodies 



