19221 Q7Q 



ROSEN — A BACTERIAL DISEASE OF FOXTAIL 676 



portion as was used in nutrient broth, 3 grams per liter. The 

 various solutions were sterilized in the autoclave at about 12 

 pounds pressure for 20 minutes. The experiment clearly indi- 

 cates that the foxtail organism not only utilizes amino acids but 

 that growth is influenced by the type of amino acid present, thus 

 the combination of alanine, leucine, and valine yields better 

 growth than leucine alone, although the total amount of amino 

 acid used was the same in both solutions. As compared with pep- 

 tone (Difco) it is interesting to note that these amino acids in 

 combination with dextrose and beef extract gave just as good a 

 growth, and in case of the leucine fraction, the growth seemed 

 heavier than in peptone media. 



Indol production. — Both the sodium nitrite-sulphuric acid and 

 the Ehrlich tests gave negative results at the end of the second, 

 fourth and tenth days. The media used were Dunham's solution, 

 nutrient broth, and one consisting of 1 per cent peptone, 0.5 per 

 cent disodium phosphate and 0.1 per cent magnesium sulphate 

 in a liter of distilled water. (Bacillus Coli gave a positive test 

 in Dunham's solution at end of the fourth day, with Ehrlich's 

 test.) It should be noted that according to the recent work of 

 Norton and Sawyer (II, '21) it appears that the old tests, such as 

 sodium nitrite-sulphuric acid, are not reliable. 



Nitrite production. — Growth in nitrate broth was fairly good ; 

 within 48 hours there was a slight growth on the surface, a 

 marked clouding and a heavy viscid growth in the bottom. 

 Tests for nitrite on the tenth day with starch water, potassium 

 iodide, sulphuric acid gave a deep blue color, indicating the pres- 

 ence of nitrites (uninoculated tubes when tested gave no color). 



Hydrogen sulphide production. — Tests with paper saturated 



with lead acetate hung over nutrient broth and over broth plus 

 potato starch showed no signs of hydrogen sulphide production. 



i. — Teats with filter naner saturated with 



Ammonia production. — Tests with filter paper 

 Nessler's reagent which was suspended over cultures in nutrient 

 broth showed a reddish brown color, rapidly developing on the 

 paper upon heating the solution, hence, that ammonia was pro- 

 duced. 



Gas production. — One per cent of the following substances were 

 used in nutrient broth kept at about 25° C. in fermentation tubes: 

 dextrose, galactose, mannite, lactose, maltose, saccharose, inu- 

 lin, and glycerin. Growth was very good in all and was sharply 

 limited to the medium contained in the open arm, medium not 



