130 Manual of Veterinary 3Iicrohiology. 



tutes another improvement, tlie first of these sub- 

 stances admitting of being raised to 39° without 

 fluidifying. The temperature of 39° is much more 

 favorable for the vegetation of germs than that of 20°. 



Inoculation of culture media. 



Inoculation of culture media should be performed 

 in such a manner as to avoid the introduction into 

 the culture medium of external germs, either from 

 the air or the surface of external objects. Air germs 

 will be avoided by considerably inclining the bulb or 

 tube to be inoculated toward the horizontal and ope- 

 rating rapidly but quietly so as not to cause agitation 

 of the air. The instruments used in transferring the 

 seed must first of all have been disinfected. These 

 instruments are : 



1st. A somewhat rigid 'platinum wire, three to five 

 centimeters in length, fused to the end of a glass 

 rod of small diameter. This wire is brought to a red 

 heat in the flame of an alcohol lamp ; as soon as it is 

 cooled the extremity is charged with a trace of the 

 seed which is then transferred to the medium to be 

 inoculated, shortening as much as possible the course 

 to be traversed by the wire in order to diminish the 

 chances of infection from the air. In the case of 

 solid media the seed may be deposited in a line on 

 the surface or in a vertical track into the substance 

 of the gelatinized mass. The appearance of the cul- 

 ture will naturally vary with these two modes. 



The platinum wire may be replaced by a needle of 

 glass, readily obtained by drawing out a fusible glass 

 rod over the lamp. 



2nd. Capillary tubes. — A glass tube is drawn out in 



