208 Dr. John Davy on the 



in minute portions mixed with common air, prevent the slow com- 

 bustion of phosphorus, as indicated by its shining in the dark, 

 have the effect, on the insects on which they were tried, of sus- 

 pending animation. 



The revival which occurred in so many instances after sus- 

 pended animation, may probably be connected with that tenacity 

 of life and long enduring excitability for which insects are re- 

 markable : thus, even when decapitated, the common house fly, 

 or the flesh fly, will not unfrequently move its hmbs twenty-four 

 hours after the loss of the head on being touched, and commonly 

 can be excited to action beyond twelve hours after such a muti- 

 lation. 



Some of the results may not be undeserving notice for practical 

 purposes, — as those in the instances of sulphuretted hydrogen, 

 oil of turpentine, and camphor, in relation to the destruction of 

 parasitical insects, whether infesting plants or minerals, or to the 

 preservation of substances from the attacks of insects. To be 

 applicable to the preservation of plants, of course it is necessary 

 that the agents to be used should not exercise on them any mate- 

 rial injurious effects. This must be determined by experiments 

 made expressly for the purpose. The few trials I have yet made 

 on seeds seem to show, that the steeping them in a solution in 

 water of sulphuretted hydrogen has not prevented their germina- 

 tion. The seeds tried were mignionette, cress seed, and that of a 

 Nemophila : analogy, viz. that of steeping the seed of the Cerealia 

 in a solution of the white oxide of arsenic, is in favour of the same 

 conclusion. Further, for the preservation of articles, whether of 

 clothing or furniture, it is hardly less necessary that the substances 

 to be employed should have no offensive odour. Judging from 

 the effects of attar of roses, and from what we know of scented 

 woods not being liable to be attacked by insects, the probability 

 is that any volatile oil of agreeable perfume will answer the pur- 

 pose required, and prove a true instance of the utile et dulce 

 combined. 



As carbonic acid gas, and some of the other agents mentioned, 

 produce merely a temporary torpor, it may be a question whether 

 this gas, or simple immersion in water, may not be advantageously 

 substituted for the fumes of burning sulphur, destructive of life, 

 at the yearly gathering of honey ; the former, indeed, may be said 

 to be in use in the Levant, where the smoke of the fire of leaves, 

 in which the carbonic acid generated may be considered as chiefly 

 operative, is employed to stupify the bees preparatory to the 

 spoiling of their hives. 



