VIABLE BACTERIA IN YOUNG CULTURES 417 



threo diluents showed that the organisms remained alive longest 

 in tap water, while in distilled water they rapidly died out. 

 With regard to saline, Flexner (1907) found that a pure solution 

 of sodium chloride was distinctly inimical to the life of the 

 Meningococcus. More recently Shearer (1919), while confirming 

 this result, pointed out that the deleterious action of this salt 

 could to a certain extent be neutralized by the addition of a small 

 amount of calcium. 



To investigate this effect more closclj', a saline emulsion of a 

 five and one-half hours' broth culture of Bact. suipestifer was 

 prepared, and roll tubes were put up from it at various intervals, 

 3 to 5 tubes being employed for each count. The emulsion was 

 put up at 3 p.m., and the counts were made each hour till 6 p.m., 

 and again the following morning at 9.30 a.m. The results were 

 as follows : 



TABLE 2 



"Sterile" = no organisms developing in a tube seeded with 0.1 cc. of the 

 emulsion. 



The effect, then, of eighteen and one-half hours' contact of the 

 bacilli with saUne, was to sterilize the emulsion. Considering 

 that this effect might be due to absence of certain salts in the 

 diluent which were necessary for the continued viability of the 

 organisms, comparisons were instituted between tap water, saline, 

 and Ringer's solution. Three sets of two flasks were taken, and 

 equal quantities of these three fluids placed in them, respectively, 

 in this order. The primary and secondary dilutions were made 

 as nearly simultaneously as possible. After performing a viable 

 count on each of these secondary dilutions, the flasks were lightly 

 plugged with cotton wool to protect them from contaminating 

 organisms. Viable counts were made at intervals up to twenty- 



