98 BACTERIOLOGY 



Collection of Sterile Tissue. For this purpose, a healthy 

 animal is first bled to death as described above (page 96) for the 

 collection of sterile blood. The skin is then thoroughly wet with 

 water or with bichloride solution. With sterile instruments, an 

 incision is made in the median line and the skin carefully stripped 

 back. It is then well to sear the abdominal wall with a hot iron 

 along the median line and also crosswise and cut along these 

 lines with sterile scissors, opening the abdominal cavity. The 

 organs desired are quickly removed with sterile instruments 

 and placed in covered sterile glass dishes. The liver, kid- 

 neys and testes are the organs most frequently employed in 

 culture media. They are divided into pieces of suitable size 

 with sterile scissors. Brain tissue may be readily obtained from 

 the rabbit. The top of the head is skinned and an opening 

 made by cutting away the skull between the orbits with the bone 

 forceps. An area of the anterior portion of the brain is exposed. 

 This is thoroughly seared with a hot iron, as well as the adjacent 

 structures. A Pasteur bulb with a large capillary (internal 

 diameter at least 5 mm.) is convenient for drawing out the 

 brain tissue. This large capillary is inserted through the seared 

 area and the brain is broken up by moving it about in the 

 cranial cavity, while the tissue is drawn into the bulb by suction. 



Pfeiffer's Blood-streaked Agar. A large loopful of naturally 

 sterile human blood, freshly taken from the ear, is spread over 

 the surface of an agar slant, and incubated to insure sterility. 

 This medium is employed for cultivation of the influenza 

 bacillus. 



Novy's Blood-agar. The agar is melted and cooled to 50 

 C. The naturally sterile defibrinated blood, usually rabbit's 

 blood, is warmed to about 40 C. The blood is mixed with the 

 agar in various proportions, and the mixture is allowed to solidify 

 in the inclined position. The medium should be fairly firm in 

 consistency and some fluid should collect at the bottom of the 

 slant. The medium is useful for cultivation of the gonococcus, 

 the influenza bacillus, streptococcus, pneumococcus and meningo- 



