Retrospective Criticism. 555 



the ravages of ^'cari, in my entomological cabinet, it struck 

 me that the same solution I had in use for the birds might be 

 applied to the insects. My fear was, that the extremely beau- 

 tiful and delicate colours on the wings of various butterflies 

 and moths might be wholly or partially destroyed. This fear, 

 however, I find, is groundless, as the finest colours remain un- 

 injured by the application. It is, however, highly necessary 

 to be cautious in the strength of the solution that is used. As 

 a general rule, one drachm of the sublimate, in fine powder, is 

 sufficient for a pint of alcohol. To prove that it is the proper 

 strength for use, Mr. Waterton's plan will be found very va- 

 luable. Dip a fine black feather into the solution, let it dry, 

 then observe if there be any white appearance left on the 

 feather ; if there be, the sublimate is in excess, and more spirit 

 must be added. This test should be repeated until no white 

 appearance remains on the feather, and it retains its black 

 glossy appearance. The best and easiest way of applying the 

 solution to insects is to immerse them entirely in it for a second 

 or two, holding them by the pin, and then dry them in a 

 current of air. It may also be applied by dropping it on them 

 from a camePs-hair brush, if you do not like to move the spe- 

 cimens ; but, by this mode, the mixture does not so well get 

 access to the abdomen, where it is principally needed. In 

 some delicate specimens, it may be necessary to reset the insect 

 when drying. Should any excess of sublimate be found on 

 the specimen, the only way of removing it is by dipping the 

 insect into pure alcohol. It may, perhaps, appear somewhat 

 superfluous to some to trouble you with these remarks; but 

 the fact is, that I have not yet met with any entomologist who 

 has applied this simple remedy. All have been still using 

 camphor, and still crying out against the " organs of destruc- 

 tiveness " of the A'cari, although it is so long since Mr. Water- 

 ton made public this plan with respect to ornithological 

 collections. Moveover, as regards expense, it will be a mere 

 trifle in an entire cabinet of entomology. Hoping that this 

 may be of use to some of your readers, I am, Sir, yours, &c. 

 — 'George H. Fielding. Hull, May 27. 1832. 



On the Subject of the Preserving of Insects in Cabinets, I agree 

 with Mr. Waterton (V. 683. VI. 90.) on the superior efficacy 

 of poisoning either the individuals or the atmosphere. In 

 the latter method, I, however, fear that the use of oil of tur- 

 pentine might be objectionable; as, in its purest state, its 

 vapour deposits a clammy substance, which, in all probability, 

 would eventually injure the specimens in the same manner as 

 Mr. Bree's were spoiled by the exudation from the cedar 

 drawers (Vol. V. p. 368.). Oil of lavender, although less fatal 



