CULTURAL CHARACTERS OF THE DAISY ORGANISM. 125 



ACIDS. 



Acetic acid is produced in peptone water in the presence of grape 

 sugar, and calcium carbonate (see report by Doctor Alsberg). Cane 

 sugar is also broken up with production of an acid. 



ALKALIES. 



The blueing of litmus milk is due to ammonia. (See under 

 Crystals [below]). 



ALCOHOLS. 



Ethyl alcohol is produced in peptone water in the presence of 

 dextrose and calcium carbonate. 



FERMENTS. 



Invertase and lab are inferred to be produced: The former because 

 an acid is produced and an invert sugar appears when the bacterium 

 is gro'^Ti in the jiresence of cane sugar; the latter because the casein 

 is thrown down without the formation of an acid. (See under 

 Litmus Milk, p. 154.) Litmus is also reduced. 



CRYSTALS. 



Prismatic crystals are formed in old cultures on agar partially 

 neutralized by sodium hydrate (+15 agar), in bouillon and also in 

 + 10 nutrient gelatin. The washed crystals from bouillon cultures 

 were determined for us by Dr. Carl L. Alsberg to be ammonium 

 magnesium phosphate. 



EFFECT OF GERMICIDES. 



Copper sulpJiate. — This organism, as shown by poured-plate cul- 

 tures, grew after 10, 15, and 20 minute exposures to 1:1,000 com- 

 mercial copper sulphate in water, which had been acidulated Nvith 

 19 drops of glacial acetic acid per 1,000 c. c. It did not grow after 

 exposure for 30 and 40 minutes. 



This experiment was repeated using copper sulphate 1:5,000, 

 acidulated ^^dth 5 drops of glacial acetic acid per liter. Plates were 

 poured after exposure of the organism to this solution for 10, 20, 30, 

 40, and 60 minutes. At the end of 6 days colonies appeared only 

 on the plates made from the 10-minute exposure. This experiment 

 was repeated a week later with the same result, namely, colonies 

 only on the check plate and on the 10-minute exposure. 



Exposures were made for 1 and 2 hours in 1 : 10,000 copper sulphate 

 water with 8 drops of acetic acid per liter. At the end of 4 days there 

 were numerous colonies on the check plate but none on the others. 



213 



