v] METHODS OF INOCULATION 63 



with extraneous organisms is more possible than by the 

 other method. 



If solid tissues or parts of tissues are required — e.g. the 

 base of an ulcer, a tubercle of the liver, spleen, or lung — it 

 is possible to squeeze into the capillary tube of a pipette, 

 after pushing its pointed end into the part, a small droplet 

 of juice of the part required ; but if this be not practicable 

 ■ — i.e. if a solid particle be required — or if it be preferred 

 because simpler, then follow Koch's method, now generally 

 used. This is as follows : Cut with clean sterile scissors or 

 scalpel into the part, take up rapidly with the point of a 

 needle or platinum wire previously heated in the flame of 

 a burner a small particle, a drop of blood, pus, juice, 

 or solid material, and quickly introduce this into the 

 culture-tube to the place required — e.g. surface or depth of a 

 solid or fluid nourishing material. Of course in this case 

 the cotton-wool must be altogether lifted, and therefore 

 contamination with air-organisms is possible. But inocu- 

 lating several tubes at once and performing the operation 

 quickly, and working in an ordinarily clean place, one 

 always succeeds in getting most of the tubes without any 

 air-contamination. I have made numerous- inoculations 

 with sohd particles of different morbid tissues and products 

 in this manner, and, like Koch and others, have seen only 

 a very small percentage of tubes becoming contaminated 

 with air-organisms, chiefly moulds. 



The same plan — i.e. of using the clean point of a sterile 

 needle or platinum wire for taking up the material to be 

 used for inoculation — is resorted to if one has to deal with 

 the culture in solid nourishing material, on or in which the 

 organisms are growing that we want to transplant either for 

 inoculation of a new tube or of an animal. A useful 

 method, which does not require the lifting out of the plug 



