554 ZAE N. WYANT AND RUTH NORMINGTON 



one to ten inclusive, the solutions being made by adding sufficient 

 broth (specific gravity taken roughly as 1.00) to 1, 2, 3, etc., 

 grams of salt to make 100 cc. Each separate concentration of 

 broth was inoculated heavily with B. botulinus so that the 

 resistant minority would survive. A layer of sterile paraffin 

 oil about 1 to 1.5 cm. deep was placed on the broth cultures, 

 which were cultivated at room temperature. Examinations, 

 macroscopic, and microscopic when necessary, were made every 

 twenty-four hours for ten or eleven days with the first five 

 strains and for seven days only with the remainder. Where 

 tubes showed no growth, transfers were made from the tube 

 of next lower concentration showing growth. Growth is shown 

 first by cloudiness, then generally by gas production (more or 

 less vigorous), followed by a precipitate, more or less heavy. 

 Where growth did not show by these signs transfers were made 

 into similar broth containing only 0.5 per cent salt and incu- 

 bated. Examinations were made of the 10 per cent salt broth 

 cultures only, after considerable periods of time as follows: 



days 



Strains G06, Mul 433, Alb 175, Alb 175B, Chi 595, C91 and GS 27 



Strain Columb 31 28 



Strains Mul 435, Mul 471, and AM of NH 31 



Strains NBS.,' Columb 1 and N. Y. City B. of H 32 



Strains Cal I, Cal II, Cal III, Cal IV and Cal VI 49 



Table 1 indicates the growth in salt broth for the nineteen 

 strains used. The occasional strains showing no growth at 

 various times and salt concentrations are indicated. 



It will be noted by examining the above table that only two 

 out of the total of nineteen strains failed to show growth at any 

 percentage of salt from 1 to 5 within the seven day period, and 

 further that these two strains were both positive at the end of 

 27 days. 



Table 2 indicates the record of the individual strains in the 

 different salt broths. In this table the + sign signifies positive 

 growth throughout the whole period of time unless otherwise 

 indicated. It will be noted that ten out of the nineteen strains 

 showed growth throughout the whole period. 



