NUTRIENT MEDIA AND METHODS OF CULTIVATION. 



125 



commonly used for accurate observations, such as Schafer's or 

 Strieker's, owing to their interference with the illumination. To 



Fig. 53. — Section' of Israel's Waeming Appabatus and Dkop-culture 



Slide. 



overcome this an apparatus has been constructed by which the 

 slide is warmed from above (Figs. 52, 53). * 



The drop-culture sUdes are provided with a shallow groove, '1 mm. 

 deep and 1 mm. broad, cut round the concavity. Into this the 

 cover-glass fits, so that its upper surface is level with that of 



Fig. 54.— Israel's Warming Apparatus. 



the slide. The heating apparatus consists of a flat disk-shaped box 

 with a central conical aperture. 



The entrance and exit pipes are fixed on at a right angle to the 



