BACTERIOLOGICAL TECHNIC 41 



blood may be mixed with agar, previously liquefied 

 and cooled to 50°, in various proportions. The a^r 

 should contain 2 to 3 per cent agar according to the 

 amount of blood to be added. 



Bread-paste medium.^-Bread is cut into slices, 

 dried in an oven, pulverized, and distributed in 100 c.c. 

 flasks until the layer on the bottom of the flask is about 

 half an inch thick. Water is added gradually until 

 the surface of the bread is moist. Sterilize in the 

 arnold. - 



Hay infusion. — 10 grams of chopped hay are 

 macerated in 1,000 c.c. water in the water bath for 

 three hours. Filter and sterilize in the autoclave. 



Wine must. — ^Wine must is diluted with four times 

 its volume of water. Dissolve o . 5 per cent ammonium 

 tartrate, macerate in the water bath for i hour, filter 

 and sterihze in the arnold for three successive days. 



Acid broth. — Add 0.5 per cent acetic acid to 

 ordinary broth. 



Calcium carbonate broth. — ^A few lumps of marble 

 added to ordinary broth. 



NITRATE MEDIA 



Nitrate broth. — ^Add 5 parts potassium nitrate to 

 each liter of ordinary broth. 



Nitrate solution. — 5 c.c. of a 2 per cent aqueous 

 potassixun nitrate solution are added to a solution of 

 I gram pepton and i gram dextrose in 1,000 c.c. water. 



