THE PAINLESS EXTINCTION OF LIFE. 6^-j 



To meet the fourth necessity, a plentiful supply of the narcotizing 

 vapor, two stoves have been connected with the chamber, each capable 

 of burning two pounds of charcoal per hour, and giving up the prod- 

 ucts of the combustion into the chamber. 



To make the narcotic effect still more certain, and to keep the 

 chamber at all times lethal, I made an extra provision. At the two 

 points where the tubes from the stoves enter the chamber, I have in- 

 terposed two strong boxes made of elm, and covered with thin lead. 

 These boxes, which are eighteen inches long and four inches broad, 

 are filled loosely with the porous burned loam known as Verity's pat- 

 ent gas-fuel, an excellent substance for filling a grate where coal-gas 

 is burned instead of fuel. This substance is so porous, it takes up 

 narcotic fluids most readily, holds them in its pores, and gives them 

 up in volumes of vapors when warm gas is passed over it. Into the 

 boxes closed in with this fuel there is a funnel, opening at the top, for 

 supplying the fluid, which can be shut with a stopper ; and at the end 

 of the box, standing out at a right angle from it, is a continuous sec- 

 tion, in which there is a large tap, for regulating the currents of gas 

 from the stove. 



When the stoves are in action, the tap is turned on, and the gases 

 from the stove pass through the boxes over the patent fuel into the 

 chamber. Nothing more is done until just before the time when the 

 animals in the cage are to be introduced. Then ten fluid ounces of 

 an anaesthetic mixture, consisting of equal parts of methylated chloro- 

 form and carbon bisulphide, are poured upon the fuel through the 

 openings in the top of the little boxes, the openings being immediately 

 closed. After the animals are in the chamber, ten ounces more of the 

 same mixture are added, and if, after three or four minutes, any of the 

 narcotized animals are still breathing, ten or twenty fluid ounces more 

 are poured in. 



In pushing the charged cage into the chamber, there is naturally a 

 very great displacement of gas or vapor within. It was necessary to 

 provide an exit which would save strain on the walls of the chamber, 

 and would let out a little gas without letting in common air. I met 

 the problem by the plan shown in Fig. 2, which exhibits the chamber 

 in section. Two feet from the far end of the chamber there is sus- 

 pended from the top a light hanging screen, which reaches within four 

 inches of the floor. Behind this screen, and in the roof of the cham- 

 ber, is a shaft, with a valve opening upward. As the cage is pushed 

 in, this screen is raised from the bottom, and the air, rushing out at 

 the lower part, ascends behind, and escapes by the valve. The screen 

 is so balanced that, when sufiicient air has been extruded, its lower end 

 reaches the back or lower end-wall of the chamber. It thus acts as a 

 regulating valve, and, when the pressure is off, it returns to its level, 

 letting any gas at the rear of it return toward the cage. 



To enable the operators to introduce the cage quickly, and at the 



