lOO BACTERIOLOGY 



and allowing the fluid to flow into sterilized flasks of looo c.c. 

 capacity which are handled by an assistant. The mouth of each 

 flask should be flamed after removing the cotton plug and again 

 before it is inserted after fiUing the flask. With proper technic 

 the ascitic fluid will as a rule be found bacteria-free. It should 

 be stored in a cool place, and is most conveniently haiidled by 

 means of large Pasteur bulb pipettes. 



In collecting hydrocele fluid or other fluids to be 

 used for' culture; media, similar aseptic technic should be 

 employed. 



Sterilization of Contaminated Fluids.^ — Any of the clear fluids 

 may be sterilized, when this is necessary, by filtration through the 

 Berkefeld filter. The filtrate will usually prove less valuable 

 as a medium than the corresponding un filtered naturally sterile 

 material. 



Collection of Sterile Tissue.^ — For this purpose, a healthy 

 animal is first bled to death as described above (page 98) 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, kidneys 

 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 



