Methods of Determination of Pathogenic Microbes. 141 



previously sterilized tube, and crushed by means of 

 a flamed glass rod, the diameter of which is a little 

 smaller than that of the interior of the tube ; steril- 

 ized bouillon is then added, and, after the particles in 

 suspension have been deposited, it is aspirated into 

 the syringe. 



Methods of inoculation. — The virus, thus prepared, 

 may be used for inoculations performed in various 

 ways, which we will now review. 



1. Endermic inoculations. — This is the simplest 

 method of inoculation ; in its performance all that is 

 necessary is to lay bare the deeper layer of the epi- 

 dermis without exciting much hemorrhage, and there 

 apply the active substance. 



The hair is clipped from the region to be inocu- 

 lated, a series of closely approximated superficial 

 scarifications made with a bistoury, and the virulent 

 substance spread over it. For this inoculation regions 

 of the body should be selected which are not easily 

 reached by licking, rubbing, etc. 



2. Subcutaneous inoculation. — The object of this in- 

 oculation is to introduce the active product into the 

 subcutaneous cellular tissue. A fold of the skin hav- 

 ing been pinched up, the canula of the syringe is in- 

 troduced at its base and the liquid to be inoculated 

 slowly expelled. It is sometimes desirable to free 

 the region from hair or feathers and render the point 

 of inoculation aseptic, by the application of a strongly 

 heated glass rod. The inoculation having been made, 

 the canula is withdrawn, and, in order to render the 

 result more certain and more rapid, the inoculated 

 point is manipulated so as to lacerate the cellular tis- 

 sue and accelerate absorption. 



