PLATE IV. 
Fie. 1.— Eprraetium Cexx from human mouth; magnified one 
thousand diameters by Zeiss’s one-twelfth-inch objective; methyl- 
violet staining; heliostat. 
Fie. 2. — ErirHertium Creu from extremity of male urethra, 
surrounded by bacteria commonly found in this location ; mag- 
nified 1000 diameters by Zeiss’s one-eighteenth-inch objective ; 
methyl-violet staining ; heliostat. 
Fic. 3.—Scales of butterfly (Satyrus zanira); magnified 100 
diameters by Tolles’s four-tenths-inch objective. 
Fic. 4. — Podura scale ; magnified 1000 diameters by Zeiss’s 
one-eighteenth-inch objective and Tolles’s amplifier. 
Fig. 5. — Scares from wing of mosquito magnified 200 diame- 
ters by Powell and Lealand’s one-half-inch objective. 
