166 BIOLOGY OF PNEUMOCOCCUS 



whose work lies chiefly in this species. But such a continued policy can 

 only render increasingly difficult important comparisons with other spe- 

 cies, and work havoc with the interests of those who are seriously at- 

 tempting to discern some law and order in the affairs of the bacteria. 

 Further advance in this direction can take place, according to my view, 

 only if bacteriologists become sufficiently keen to recognize the true na- 

 ture of the phases they employ, and sufficiently independent to "call a 

 spade a spade," whenever recognized as such, regardless of politics, tra- 

 dition or social etiquette. . . . 



It might also be in the back of your mind that the splendid work of 

 some of your associates on the chemical aspects of dissociation would 

 suffer from any change in terminology made at this late date. I am ab- 

 solutely convinced to the contrary. In reality I believe that the incen- 

 tive to extensions of their results to many other bacterial species would 

 be a direct and immediate outcome, through establishing a recogni- 

 tion of the most appropriate culture phase to be employed in such 

 studies. . . . 



It is therefore my opinion that a frank recognition of the present 

 incongruities of the situation will not detract from, but facilitate in 

 wide measure, researches in the important field opened up years ago by 

 Drs. Avery, Dochez, Heidelberger and their collaborators. 



Dawson believed that before making such a radical change in the 

 accepted terminology of pneumococcal variants it would be well to 

 ascertain if similar variants could be demonstrated in Streptococ- 

 cus haemolyticus. From the latest study by Dawson, 303 it would 

 seem that he succeeded in dissociating that organism into three 

 main variants, which in their manner of colony formation and in 

 morphology correspond closely with the three main variants of 

 Pneumococcus. The mucoid and smooth forms appeared and, by 

 cultivation of the streptococci on blood agar and by repeatedly 

 picking and transplanting material from the roughest marginal 

 areas, Dawson was able to develop the extremely rough type of 

 colony which he had obtained with pneumococci, representing the 

 R variant. 



As Dawson said, "evidence is rapidly accumulating to show that 

 the phenomenon of bacterial variation in a wide variety of bac- 



