78 A MANUAL OF BACTERIOLOGY 



Serum agar. This may be prepared by adding sterile 

 serum or hydrocele or ascitic fluid, warmed to 45 C., 

 to sterile nutrient agar (2 to 3 per cent, agar) melted and 

 cooled to 45 C. Equal parts of the serum and agar may 

 be mixed, or one part of serum to two or three parts of 

 agar is usually sufficient. It must not be sterilised. 



Blood agar. This may be prepared by smearing the 

 surface of the agar in sloping agar-tubes with blood 

 obtained aseptically from the finger or from a rabbit. 

 Or blood obtained aseptically may be defibrinated by 

 shaking with glass beads or with a coil of fine wire, and 

 the defibrinated blood, warmed to 45 C., is added to 

 sterile agar liquefied by boiling and cooled to 45 C. 

 Haemoglobin agar may be prepared by laking defibrinated 

 blood by the addition of sterile distilled water and adding 

 to the liquid agar as before. Blood agar cannot be 

 sterilised alter preparation, and the blood therefore must 

 be sterile. 



Noguchi's medium. For the cultivation of certain 

 organisms which refuse to grow on all the ordinary media, 

 Noguchi makes use of serum, serum broth, simple or 

 glucose agar or gelatin, to which is added a piece of 

 rabbit kidney, removed with careful aseptic precautions. 

 Anaerobic cultivation is generally required. 



Alkali albumen (Lorrain-Smith). To 100 c.c. of fresh 

 serum add 1 to 1-5 c.c. of a 10 per cent, caustic soda 

 solution ; mix and introduce into test-tubes in the 

 ordinary way. Place the test-tubes in the slanting 

 position in the autoclave at 115C. for twenty minutes, 

 or in the steamer on three successive days. 



Egg cultures (Hueppe). These are very useful for some 

 purposes. A hen's egg is taken and one end sterilised 

 by washing with carbonate of soda solution, rinsing in 

 sterile water, soaking in 1-500 corrosive sublimate solu- 

 tion, and washing in alcohol and in ether. A small hole 



