156 BACTERIOLOGY 



ment has occurred essentially the same conditions as regards 

 separation of the colonies will be found as when plates are 

 poured. If a slanted medium be employed, about the most 

 dependent angle of which water of condensation has accu- 

 mulated, as blood serum, agar-agar, and potato, the dilu- 

 tions may be made in this fluid, and this is then to be carefully 

 smeared over the solid surface of the medium. The tubes 

 thus treated should be kept in an upright position to pre- 

 vent the fluid flowing over the surface. When sufficiently 

 developed, single colonies may be isolated with comparative 

 ease from tubes prepared in this manner. (See also method 

 for the isolation of bacillus diphtherise on blood serum.) 



