THE GENUS DIPLOCOCCUS 



examined in detail eighty-four different cultures of forms 

 allied to the pneumococcus, isolated from sputum and 

 from various pathological conditions, and observed 

 marked variations but no clearly denned varieties. "We 

 find," they conclude, "a certain sum of common charac- 

 ters which taken together give a picture of the Diplococcus 

 lanceolatus capsulatus but we find also numerous differ- 

 ences, quantitative and qualitative, in virulence, in growth 

 characters and in viability." Morphologically, all grada- 

 tions appeared between cultures which showed chains 

 of spherical cells with faint capsules and those which 

 showed, almost exclusively, typical pairs of encapsulated 

 lanceolate cells. Continued cultivation on artificial media 

 tended to develop more and more clearly the first type 

 of growth, while animal inoculation often restored the 

 second. Virulence could be diminished or increased by 

 proper treatment. Those forms which most resembled 

 Sir. pyogenes in morphology showed also a more vigor- 

 ous growth on artificial media, and at low temperatures. 

 Coagulation of milk varied notably in different strains, 

 and in the same strain at different times. 



Kindborg (1905) has recently emphasized again the 

 existence of numerous slightly differing varieties among 

 organisms supposed to be pneumococci. He studied 

 twenty-four races from sputum and pus, arid among 

 these, some were constantly larger or smaller than the type, 

 and others showed a definite tendency to chain forma- 

 tion. Variations in vigor of growth and in temperature 



