240 THE USE OF THE MICROSCOPE 



88. Cells from Mouth Showing Brownian Movement. — 

 Use water-immersion objective 70, or oil immersion 60 of 

 1.05 aperture and dark-field condenser. Cover 0.16 to 0.17 

 millimeter thick. 



89. Living Muscle Fiber. — From leg of bee or beetle. 

 Mount in fluid from thorax. Water-immersion objective 

 70. Also in polarized light with tourmalin before source 

 and over eyepiece. Also dark field. 



90. Structure of Drosophila. — Male and female mounted 

 in immersion oil, after absolute alcohol, cedar oil, and 

 xylol. Also the hard parts alone, mounted in immersion 

 oil after treatment with caustic soda, water, alcohol, cedar 

 oil, and xylol. 



91. Mutants of Drosophila. — Some of the chief mutants 

 showing structural differences, mounted as in 90. 



92. Amoeba. — In large numbers in cultures. Treat as in 

 78 to 84. 



93. Vorticella. — Division. Water-immersion objective 

 70. Also dark field by central stop on immersion con- 

 denser, and apochromatic objective 20, with cover-glass 

 0.17 millimeter thick. 



94. Paramoecium. — From culture. As in 93. Also 

 nigrosin smear. 



95. Ontogeny of Sponge. — Grantia, living. As in 93. 



96. Foraminifera, Living. — On the thin side of a glass 

 trough of sea water, showing cytoplasmic net. Greenough, 

 horizontal. 



97. Larva of Sea Urchin and of Starfish. — Living; and 

 also fixed, and stained with Mayer's carmalum. 



98. Circulation in Frog's Lung or Mesentery, or in 

 Larval Teleost. — Use apochromatic objective 20, corrected 

 for uncovered objects by extending tube about 35 milli- 

 meters (or put on cover, 0.17 millimeter thick). 



99. Living Cells, in Hanging Drop, from Tissue Cultures. 

 Embryo chick. Water-immersion objective 70. 



100. Phagocytosis. — Smear showing gonococci or men- 

 ingococci in leucocytes. Fixed and stained. 



