METHOD OF PRESERVING INSECTS. 527 



METHOD OF PRESERVING INSECTS. 



I ONLY know of two methods to guard prepared insects from the 

 depredations of living ones. The first is by poisoning the atmos- 

 phere ; the second is by poisoning the preserved specimens them- 

 selves, so effectually, that they are no longer food for the depredator. 

 But there are some objections to both these modes. A poisoned 

 atmosphere will evaporate in time, if not attended to, or if neglected 

 to be renewed ; and there is great difficulty in poisoning some speci- 

 mens on account of their delicacy and minuteness. If you keep 

 spirits of turpentine in the boxes which contain your specimens, I am 

 of opinion that those specimens will be safe as long as the odour of 

 turpentine remains in the box; for it is said to be the most pernicious 

 of all scents to insects. But it requires attention to keep up an 

 atmosphere of spirits of turpentime. If it be allowed to evaporate 

 entirely, then there is a clear and undisputed path open to the inroads 

 of the enemy : he will take advantage of your absence or neglect, and 

 when you return to view your treasure, you will find it in ruins. 

 Spirits of turpentine, poured into a common glass inkstand in which 

 there is a piece of sponge, and placed in a corner of your box, will 

 create a poisoned atmosphere, and kill every insect there. The 

 poisoning of your specimens by means of corrosive sublimate in 

 alcohol is a most effectual method. As soon as the operation is 

 properly performed, the depredating insect perceives that the pre- 

 pared specimen is no longer food for it, and will for ever cease to 

 attack it. But, then, every part must have received the poison ; 

 otherwise those parts where the poison has not reached will still be 

 exposed to the enemy ; and he will pass unhurt over the poisoned 

 parts, till he arrive at that part of your specimen which is still whole- 

 some food for him. Now, the difficulty lies in applying the solution 

 to very minute specimens, without injuring their appearance ; and all 

 that can be said is, to recommend unwearied exertion, which is sure 

 to be attended with great skill ; and great skill will ensure surprising 

 success. I myself have attended to the preservation of insects with 

 the assiduity which Horace recommends to poets : " Nocturna 



