ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
251 
Swift’s New Histological and Physiological Microscope. — This 
instrument, represented in figs. 17 and 18, is specially designed to meet 
the requirements of students in general biological work. The optical 
tube is provided with a draw-tube divided in mm. The coarse-adjust- 
ment is by the spiral rack -and -pinion motion patented by the makers, 
while the fine-adjustment is by micrometer-screw of entirely new con- 
s 2 
