204 Dr. John Davy on the 



of life for an hour or two, it revived, and recovered its activity. 

 Replaced, and kept exposed to the acid vapour for twenty-four 

 hours, it was found dead when taken out. 



A fly (Piophila casei) was put under a small wine glass, on a 

 glass support, and with it a portion of cottonwool moistened with 

 the acid. In less than a minute the gait of the fly became tottering ; 

 and in less than five minutes it was motionless. It was imme- 

 diately taken out, but it did not revive. A similar experiment 

 was made on another fly {Heteromyza ?), somewhat larger and 

 more vigorous. After about a quarter of an hour it became 

 motionless. Then taken out, in a few minutes it became pretty 

 active. 



Nitric Acid. — The results of two trials with the vapour of this 

 acid, one on a I'iophila, the other a Heteromyza, differed chiefly 

 from those last mentioned in being, in each instance, fatal, exhi- 

 biting, after deprivation of motion, no sign of revival, though 

 taken out immediately. 



Alcohol. — Put a fly (Musca lanio) into a tube with a little alcohol 

 of Sp. Gr. '84 underneath, and raised its temperature to 74°. 

 For a few minutes the fly showed increased activity ; in a few 

 more it became nearly motionless ; after about a quarter of an 

 hour it appeared to be torpid. Now, exposed to the air of the 

 room, in a few minutes a slight motion of its feet was seen ; after 

 a couple of hours it was nearly as active as before the experiment ; 

 two hours later it was found dead. 



On the 8th of January, temperature of the room about 58°, 

 placed two small flies (Sciara vitripennis, Psychoda nervosa) under 

 a wine glass, on a glass support, with a portion of cotton-wool 

 moistened with alcohol. The first effect was an increase of acti- 

 vity ; after a few minutes their irregular movements and occa- 

 sional falls suggested an inebriated state. A drop of alcohol 

 poured on them rendered them motionless instantly, and proved 

 fatal to them. 



On the 11th January a similar trial was made on another fly 

 (Heteromyza buccata), at a raised temperature of 70°. The excite- 

 ment first produced, marked by increased activity, was soon fol- 

 lowed by feebleness, irregular movements, and death. Similar 

 effects were produced by the vapour of alcohol on another fly of 

 the same kind, at the temperature of the room 57°, but not quite 

 so rapidly. 



Ether. — On the 12th January placed a fly (Musca lanio) in a 

 tube with a little sulphuric ether, at the temperature o( the room 



