408 REPORT— 1869. 



As it soon became apparent that, under all forms of administration, the 

 results were mateiiaRy modified by temperature, care was taken to secure, 

 in analogous experiments, the same ranges of temperature. This was efifected 

 by means of specially constructed chambers, into which the air could be ad- 

 mitted in measured quantities, and in which the air or atmosphere could be 

 maintained for any length of time at a nearly fixed degree, the variations at 

 the extremest being imder three degrees in Fahrenheit's scale. (The chamber 

 was defined in a diagram. In it the air could be raised to 120^ Fahr. and 

 sustained at that heat, or reduced to 10° below freezing-point and kept at that 

 low temperature steadily.) 



Another chamber was also used in experiments where inhalation of an 

 atmosphere charged with a foreign gas or vapour was not wanted ; this con- 

 sisted of a simple metal chamber with a double hning, through which warm 

 or cold air could be passed at pleasure. Within it was slung a cradle lined 

 with thick felt, made after the manner of a hammock. In this chamber the 

 air could be readily raised to a temperature of 160°, or even 200° Fabr. ; but 

 the chamber was not air-tight, and was not adapted for holding in circuit 

 atmospheres of common air mixed with vapours or gases. It was always 

 well ventilated vrith pui'e air, and was used for inducing recovery, or for 

 proving the conditions adverse or favourable to recoveiy from certain of the 

 agents employed when they were administered in excess. 



The classes of animals subjected to the vapours or fluids were batra- 

 chians, birds, small herbivorous and carnivorous mammals. In every in- 

 stance where comparative inquiilcs were made the utmost care was taken to 

 estimate mere apparent difi"erences of phenomena from the same agent from 

 differences in the character or constitution of the animal submitted to the 

 action of the agent. The natural temperatures of all the warm-blooded 

 animals was recorded from time to time, and the mean temperature was cal- 

 culated and adopted as the natural standard. 



Advantage was taken of difi'erent seasons of the year, and of extreme 

 natural variations of heat and cold, for the carrying on of many of the in- 

 qiiiries. This point of practice, followed out at first without reference to any 

 other than the present research, was found to have a distinct and important 

 bearing on the general question of the use and administration of chemical 

 medicinal agents. 



I now pass to the first part of this Report, taking up the study of the 

 groups of substances in the order of the Tables. 



PART I.— THE NITRITE SERIES. 



In previous Reports I have called the attention of the Section to the action 

 of the nitrites of methyl, ethyl, and amyl. I have experimcuted during the 

 past year with the nitrite of butyl, and have thus completed the elementary 

 study of the group up to the amyl or pentylic series. The specimen of nitrite 

 of butyl I used was made for me by Professor Wanklyn. It is obtained by 

 the action of nitrous acid upon butylic alcohol. 



Xitrite of butyl is a slightly coloured fluid, having an odour like nitrite of 

 amyl, but it is not so overpowering. Its physiological action is nearly the 

 same as that of nitrite of amyl, but less iuteuse and protracted ; it quickens 

 the pulse, produces suffusion of the countenance, causes great oppression on 

 the brain, and those singular noises or sounds in the head which resemble 

 the sounds produced by the rusluug of water. The breathing also is affected, 

 and the respiratory muscles are influenced as after running sharply until out 

 of breath. In a case where a young friend of mine (who has naturally a 



