Effects of certain Agents on Insects. 205 



56°. It immediately became motionless. Taken out after a few 

 minutes it soon revived, and seemed as active as before. Replaced 

 in the tube after an interval of two hours, it did not become 

 torpid so soon as at first, two or three minutes elapsing ; it revived 

 in about a quarter of an hour after being taken out. 



Repeated the experiment on another fly (Heteromyza buccata) 

 at a temperature of about 54°. In a few seconds the fly dropped 

 from the side of the glass motionless ; so it continued till taken 

 out. Taken out, after ten minutes, it did not revive. Repeated, 

 on another fly of the same kind, the immediate effect was the 

 same. Taken out, in less than a minute, in about an hour it re- 

 vived and was active as before. 



Chloroform. — On the 14th January, at the temperature of the 

 air of the room, placed a fly of the same kind as the last under a 

 wine glass, with a portion of cotton-wool moistened with chloro- 

 form. For a second or two the insect was active; then it sud- 

 denly became motionless. Taken out, it was tolerably revived in 

 an hour. Repeated the experiment on a small gnat, with a like 

 effect in every respect. Repeated it on the fly and the gnat, 

 keeping them in the vapour about eight minutes ; they soon be- 

 came motionless as at first, but they did not revive on exposure to 

 the air. 



Camphor. — A fly (Heteromyza buccata) put under a wine glass 

 at the temperature of the room, with a piece of camphor, became 

 torpid in about half an hour; after exposure to the air for about 

 the same time it revived, moving sluggishly. Replaced, and left 

 over night under the glass, with the camphor, on the following 

 morning it was found dead. Repeated the experiment with ano- 

 ther fly of the same kind. In rather less than half an hour its 

 activity was diminished ; some five hours later it was motionless; 

 it did not revive on exposure to the air. 



Oil of Turpentine. — On the 20th January placed two flies, of 

 the same kind as the last, under a wine glass, with a portion of 

 cotton wool moistened with this volatile oil. In a minute or two 

 they walked unsteadily, as if intoxicated ; in less than a quarter 

 of an hour they were found motionless, they had become smeared 

 with the oil ; they did not revive on exposure to the air. Another 

 fly, of the same kind, placed in a tube with a portion of oil, sepa- 

 rated by a diaphragm, pervious to the vapour, at a temperature of 

 about 75°, soon became motionless, and did not recover when 

 taken out. Repeated the experiment on another fly of the same 



