COMPARATIVE STUDY OF THE COCCI 73 



fully discussed above. It should be noted, however, 

 that group 5 includes certain laboratory cultures whose 

 origin was unknown. 



2. Grouping of cells and dimensions. Observed in 

 stained preparations, made from 20-degree agar cul- 

 tures less than five days old. Grouping recorded as 



1 (packets present), or 2 (packets not present). Extreme 

 dimensions recorded in micro-millimeters to the nearest 

 tenth. 



3. Relation to Gram stain. Observed on two different 

 occasions; on 20-degrees agar cultures less than five days 

 old. Treated with anilin-oil-gentian-violet for ij min- 

 utes; Gram's solution, i^ minutes; 95 per cent alcohol, 

 3 minutes. Counterstained with Bismarck brown for 

 one-half minute. Reaction recorded as — (decolorized in 

 both tests); ± (stained once and decolorized once); or 

 + (stained in both tests). 



4. Vigor of surface growth on agar streak after 

 14 days at 20 degrees. Recorded as 1 (very faint); 



2 (meager); 3 (good); 4 (abundant); or 5 (very 

 heavy). 



5. Amount of acid produced in 2 per cent dextrose 



broth after 14 days at 20 degrees. Determined by 



N 

 titration against — NaOH in the cold with phenolphtha- 

 20 



lein as an indicator. Recorded value is the difference 



between inoculated tubes and sterile controls, expressed 



as per cent of normal. 



