GENERAL PRINCIPLES 151 



1881, Gonococcus 1879-85, Pneumobacillus 1883, Pneumo- 

 coccus 1884, Meningococcus 1885, Tubercle bacillus 1882, 

 Bacillus mallei 1882, B. typhosus 1880-84, B. coli, 1886, 

 Klebs-Loeffler 1883-84, Micrococcus meh'tensis 1887, B. 

 enteritidis 1888, B. tetanus 1884-89, B. pestis 1894, {B. 

 enteritidis sporogenes 1895, Cholera v. 1883, B. botulinus, 

 B. paracolon and paratyphosus, and B. Morax-Axenfeld, 

 all in 1896. 



CHAPTER IX. 

 GENERAL PRINCIPLES. 

 BACTERIOLOGICAL MEDIA 

 may be thus classified : 



Nutrient Broth, standardized. 



Derivatives : Glucose broth, lactose broth, nutrient 



gelatin, nutrient agar-agar, glycerin agar, glucose 



agar, lactose agar. 

 Peptone Water. 



Derivatives : Glucose peptone water, lactose 



peptone water, sucrose and mannite peptone 



water. 

 MacConkey's Media. Bile-salt litmus glucose peptone 



water ; bile-salt neutral-red lactose agar. 

 Other Media. Milk, potato, blood serum, ascitic fluid, 



urine, whey, gelatin agar, beer wort, bread, 



eggs ; nitrate media, synthetic media ; animal 



tissues, etc. 



Nutrient Broth. 500 grm. of lean beef finely minced 

 are steeped in one litre of ordinary water for twenty-four 

 hours in a cool place. The fat particles are then skimmed 

 off, the fluid strained off, and the juice well pressed out. 

 This is then boiled for half an hour to coagulate the 

 albumins, filtered, and the bulk made up to I litre. One 

 per cent of Witte's peptones and | per cent of common salt 

 are then added and dissolved by the aid of heat. The 

 broth is now tested as to its reaction, and is usually acid. 

 Its acidity is determined by taking 5 c.c., diluting to 50 c.c. 



