NEOPLASTIC ABNORMAL GROWTH 235 



"The data obtained by chemical, enzymatic, and serological analyses 

 together with the results of preliminary studies by electrophoresis, 

 ultracentrifugation, and ultraviolet spectroscopy indicate that, within 

 the limits of the methods, the active fraction contains no demonstrable 

 protein, unbound lipid, or serologically reactive polysaccharide, and con- 

 sists principally, if not solely, of a highly polymerized, viscous form 

 of desoxyribonucleic acid. On the other hand, the Type III capsular 

 substance, the synthesis of which is evoked by this transforming agent, 

 consists chiefly of a non-nitrogenous polysaccharide constituted of 

 glucose-glucuronic acid units linked in glycosidic union. The presence 

 of the newly formed capsule containing this type-specific polysaccharide 

 confers on the transformed cells all the distinguishing characteristics 

 of Pneumococcus Type III. Thus, it is evident that the inducing sub- 

 stance and the substance produced in turn are chemically distinct and 

 biologically specific in action and that both are requisite in determining 

 the type specificity of the cell of which they form a part." 



Information which is perhaps pertinent to a better understanding 

 of the unique qualities of the cancer cell may be derived also from 

 studies of the factors which make a bacterium pathogenic. The loss of 

 the O type specific polysaccharide characteristic of the S— >R variation 

 of gram negative bacilli, like the loss of the specific polysaccharide of 

 the pneumococcus, is associated with loss of virulence. The M sub- 

 stance of group A streptococci gives type-specificity and seems to be 

 characteristic of all virulent strains. It is usually supposed that the dis- 

 appearance of characteristic substances in bacterial variants is due to 

 the fact that these substances are not produced. It may be, on the other 

 hand, that in the variant cells the special substances are metabolically 

 broken down by the acquisition of new functions. Although it is usually 

 stated that the non-specific or undififerentiated bacteria have lost the 

 ability to produce the O antigens or the capsular polysaccharide or 

 the M protein, the possibility has not been ruled out that in the trans- 

 formation from dififerentiated to undififerentiated cells they have be- 

 come able to metabolize those substances further and hence do not 

 accumulate them in recognizable form. Perhaps by this concept an 

 analogy can be drawn between bacterial variation and the differentia- 

 tion of mammalian cells. The assumption by tissue of special characters 

 and powers coincident with maturation may actually represent discon- 

 tinuous variations which involve the inability to carry certain reactions 

 to completion, with the consequent accumulation of the products of 

 these incomplete reactions. 



