OPERATING-ROOM AND FIXTURES. 59 
The screen is adjustable in a perpendicular direc- 
tion within the limits required. The arrangement 
for focusing consists of a pulley two and a half or 
three inches in diameter, which is fastened to the 
shelf which supports the microscope, in the same 
plane as the head of the fine-adjustment screw. 
A cord connects the two, so that the fine adjust- 
ment is controlled by moving the large pulley. 
The axis of this pulley projects towards the screen, 
and is square at the extremity for the reception of 
a key — like aclock-key — by which the pulley is 
operated. This key is attached to the end of a 
rod jointed like a fish-pole, which gives the opera- 
tor control of the fine adjustment at any required 
distance from the screen. 
Dr. Woodward has his microscope placed at such 
a height that the eye-piece is on a level with the 
eye of the operator when he is in a sitting posi- 
tion. The present writer, as already stated, prefers 
a standing position. This elevation of the instru- 
ment is also necessary when the screen is arranged 
in the manner about to be described, and the 
author’s contrivance for focusing is adopted. 
Instead of supporting the screen from the floor, 
the writer prefers to have it suspended from above, 
and movable in a right line corresponding in 
direction with the axis of the microscope. The 
focusing arrangement is essentially that already 
described (p. 51), but it is applied to the fine adjust- 
ment only, as the operator, standing at the micro- 
scope, can see the image upon the screen, and can 
focus roughly from this point. The cord, passing 
