For many years various forms of ether valves have been in use in experimental laboratories.1 The arrangement described below has been found, after several weeks' trial, to be more nearly free from objections than any other form of valve which has been in general use.
The valve consists essentially of a brass box, 5.5 cm. long, 3 cm. deep and 3.7 cm. wide. An interior partition divides the box into two compartments. A tube, a (and a′), 1.1 cm. in diameter and 5 cm. long, enters one endof the box. Air passes in through this tube. At b′ the entering air comes in contact with a door-shaped valve (b′) which can be instantly set at any angle by means of the small lever b, seen in Figure 1. The angle at which this valve is set regulates the relative amounts of air and ether vapor which the animal breathes.
JACKSON DE. AN ETHER VALVE FOR USE IN ANIMAL EXPERIMENTATION. JAMA. 1912;LVIII(7):475–476. doi:10.1001/jama.1912.04260020159012