PREPARATION OF CULTURE MEDIA 



By placing weights to correspond to this amount on the 

 left side of the scales, and the saucepan with contents 

 on the other side, the weight can be readily adjusted. 



ii. Heat again to the boiling-point, and filter the 

 liquid into culture-tubes to about one-third of their 

 length (7 c.c.). 



Method of filtering media. Arrange two funnels, a 

 pipette with hose, and a pinchcock on the retort-stand, 

 as illustrated in Fig. 5. Place a strainer made of per- 

 forated tin (Fig. 6) against the side of the saucepan, 



FIG. 7 

 Strainer in Position 



near the top, as illustrated in Fig. 7, and pour the medium 

 into the larger funnel holding the filter. 



For the purpose of filtering the medium either white 

 filter-paper of the best quality or absorbent cotton may 

 be used. A filter-paper folded in the following manner 

 is very serviceable: 



i. Take a square piece of filter-paper twice as wide 



