LABORATORY AND GREENHOUSE STUDIES. 101 



Dunham's solution plus litmus with and without grape sugar, reduc- 

 tion either entire or partial took place. 



In the Dunham's solution cultures containing indigo carmine 

 there was no reduction either in the tubes with sugar or in those 

 without. 



In the Dunham's solution cultures containing methylene blue 

 there was no reduction in color except in one tube containing the 

 grape sugar. 



From these experiments it would seem that a reducing agent is 

 not always produced and does not affect all colors. As seen on 

 other pages (pp. 69, 80, 1 15) cultures were made in neutral red and in 

 rosolic acid. In these cases, however, the action was a complex one 

 caused by the presence of an acid or an alkali, so that a clear reducing 

 action could not be determined; there would seem to be one in 

 neutral red but not in rosolic acid. 



Growth on Miscellaneous Culture Media. 



The media used in the following experiments are for the most part 

 such as are commonly used in general cultural studies of a bacterial 

 organism. In some cases they have little or no value in diagnostic 

 work, but they serve as means to increase our knowledge of the hfe 

 processes of the organism under investigation. In a few cases the 

 media used were originally recommended by their authors as means 

 of diagnosing or differentiating Bacillus coli from other organisms. 

 For various reasons, under the writer's manipulations some of these 

 tests have failed of their original purpose, but will here serve well as 

 a means of comparison between the coconut organism and Bacillus 

 coli. 



NITROGEN-FREE MEDIA. 



Cultures were made in a nitrogen-free nutrient medium plus various 

 chemicals containing nitrogen to ascertain from which the organism 

 could obtain its supply. Three salts of ammonium (tartrate, citrate, 

 and lactate), asparagin, and sodium asparaginate were used. The 

 nutrient medium was made up in the proportion of 1,000 c.c. triple 

 distilled water, 5 grams of cane sugar, 2 grams of monopotassium 

 phosphate, 0.1 gram of magnesium sulphate, and 0.5 gram of sodium 

 chlorid. 



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