246 PEARL— EFFECT OF CERTAIN POISONS 



In the present experiments inhalation tanks of two different sizes 

 have been used. They are essentially square boxes of galvanized 

 iron, having at the top a round opening which serves as a means of 

 entrance and exit for the bird. This opening is tightly closed by 

 a cover during an experimental treatment. Below the bottom of 

 the tank is a cylindrical reagent chamber closed by a tight fitting 

 cover from below. In this projection below the floor of the tank 

 proper is placed absorbent cotton saturated with the particular re- 

 agent used. Over the top of the reagent chamber is placed a piece 

 of heavy galvanized wire gauze of about half-inch mesh which 

 serves to complete the floor of the inhalation compartment proper, 

 without obstructing the diffusion of the fumes from the reagent 

 chamber. 



Regarding the mode of administration of the poisons used it was 

 found early in the work to be undesirable to depend entirely upon 

 the evaporation of the reagent from cotton in the chamber at the 

 bottom of the tank. This process took altogether too long a time 

 to saturate the air of the tank wnth the vapor. Practically from 

 the beginning we have used a combination of this method plus a pre- 

 liminary saturating of the air with the vapor of the substance used 

 by means of an atomizer. The routine procedure is this : there is 

 placed in the reagent chamber at the bottom of the tank a piece of 

 absorbent cotton soaked with the reagent to be used, ethyl or methyl 

 alcohol or ether, as the case may be. Then the operator quickly but 

 thoroughly fills the whole of the tank proper by means of an 

 atomizer with a saturated vapor of the same substance. The birds 

 to be treated are then introduced quickly, allowing as little as possible 

 of the vapor to escape in the process. When the birds have been 

 introduced the cover of the tank is tightly closed and left in that 

 condition for one hour. It is to be understood throughout this 

 paper that every bird designated as a " treated bird " has spent one 

 hour every day in one of these tanks subjected to the fumes of the 

 reagent specified in the particular case. 



The number of treated birds used in the experiments to the date 

 covered in this report is 19. The number of untreated control 

 brothers and sisters is 58. 



