140 Manual of Veterinary 31icrobiology . 



may, in an emergency, be brought into use for experi- 

 mental inoculation, but there are some which are pre- 

 ferred on account of their great susceptibility for most 

 of the bacterial diseases and of the ease with which 

 they can be obtained. 



The animals which are the most used are the 

 guinea pig, rabbit, rat, mouse, chicken, pigeon, and 

 small birds. In exceptional cases the large domes- 

 ticated animals are employed. 



Inoculation ' substances.— YvYxilQui substances used 

 for inoculation should, as far as possible, be free from 

 all microbic mixture, and the Pravaz syringe and 

 other inoculation instruments should previously be 

 rendered aseptic. 



If the product to be inoculated is a bouillon culture, 

 this fluid is turned, after shaking, into a previously 

 flamed watch glass, and quickly aspirated into the 

 syringe. 



If the culture has been made upon a solid medium 

 a quantity of the material is taken upon a sterilized 

 l)latinum wire and diluted in a little sterilized water 

 or bouillon. 



"When we have to do with fluid pathological pro- 

 ducts (blood, milk, pus, etc.) these products, col- 

 lected in a pure state from the living being or from 

 the cadaver, are employed in the way just described. 

 In some cases they are previously diluted. 



Sometimes the virulent substance is a solid patho- 

 logical product. This product, free from all con- 

 tamination, is crushed in a special mortar, diluted in 

 bouillon, which is then strained through fine linen. 

 To more com.pletely avoid the external germs the 

 virulent particle may be introduced into a small 



