a slight rise, and died at 105°.  A bee, taken on March 15, from a temperature of 45°, was exposed to 80° without any apparent diminution of activity; at 90° it ceased to buzz; and at 96°, ceased altogether to move, and did not revive.  Although these results are too few to enable us to determine the laws with respect to the influence of temperature on insects, they may serve a purpose, in shewing that the effect is not that gradual one of hybernation, where activity and torpor succeed each other but slowly.

In the series of experiments with gas, it was found that flies placed in carbonic acid gas became instantly motionless, and died if left for any length of time.  Some revived after an hour’s immersion; others, after two or three hours—­the revival being slow in proportion to the time of exposure to the gas.  Somewhat similar results were obtained with flies and bees in hydrogen and azote.  To try the effect of deprivation, a fly was shut up in a tube with but a small quantity of common air, on the 5th February, in a temperature varying from 52° to 60° during the whole time of the experiment.  The insect manifested no uneasiness until the 25th day, and was found dead on the 28th.  Another fly, enclosed in a similar tube, with a quantity of air not more than a few times its own volume, became languid on the second day, and motionless on the twelfth, but revived on being taken out.

Flies immersed in oxygen were found dead the second day, with a diminution of the quantity of the gas.  Coal-gas produced almost immediate insensibility, with a few feeble attempts at revival, but in no case effectual.  Sulphuretted hydrogen also proved especially fatal—­an instant’s immersion was sufficient to destroy life; though withdrawn at once, not one of the flies recovered.  It was the same when the portion of gas diffused in the air of the tube was so minute as to be scarcely appreciable.  On bees, too, the effect was similar; the deadly nature of the gas on their delicate organisation being invariably destructive.  Like results were obtained with chlorine.

In the class of vapours, ammonia proved fatal in one case, and harmless in another; muriatic acid stupified in two, and killed in twenty-four hours.  The vapour of nitric acid was equally fatal with sulphuretted hydrogen; and, in alcoholic vapour, at a temperature of 74°, ’for a few minutes the fly shewed 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.’  The same effects, with slight variations, were produced on other flies.  With ether, cessation of motion was almost instantaneous, followed, however, by revivification, except in one instance:  brief immersion in chloroform did not prevent revival, but an exposure of eight minutes killed:  camphor and turpentine were both fatal:  with attar of roses, musk, or iodine, no ill effect was perceptible.