^ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 



637 



produce contrasts in the illumination whereby, even in unstained pre- 

 parations, structural details are disclosed which hitherto have required 

 special staining f methods. The reflecting condensers should preferably 



Fig. 99. 



Jjlllllllllllllllllllli 



I 11 iil I 



Fig. 100. 



