INSECT MEDICINES — CANTHARIDES. 231 



say is this — ' We must procure a large quantity of the next best timber to 

 oak, and only use oak where nothing else does so well.' Your blue gum 

 has been strongly recommended to the Admiralty ; and Sir William Denison 

 and others have written to me most strongly in its favour. Now I am truly 

 glad to hear this, as I believe that, if once extensively introduced into the 

 country, there would be a great and continued demand. But I should not 

 like the Admiralty to estimate the value of the blue gum beyond its real 

 merits. I believe it has great merits, without having some of the rare 

 qualities of the oak. Is it not so ? 



" So great is the demand for timber that the Admiralty are now, at con- 

 siderable expense, making search by means of competent persons. 1. In 

 North China and Japan. 2. On the West Coast of Africa, and in Fer- 

 nando Po. 3. In British Guiana, and far up the rivers there." 



INSECT MEDICINES— CANTHARIDES. 



From insects we derive articles of commerce of no mean importance, 

 especially the products of the silk-worm, the honey-bee, the lac insect, and 

 the cochineal insect. Wax and Lae have already been noticed in the pages 

 of the Technologist, and we shall now advert to some other products. 

 Insects once formed a class of medicines which were considered highly 

 effective in certain cases ; and there was a time when three gnats were 

 taken as a dose just as three grains of calomel might be taken now ; while 

 three drops of ladybird milk were formerly prescribed as seriously as a 

 small dose of some fashionable medicine of the present day. Wood lice and 

 ants were used, and many beetles prescribed, for relieving toothache. It 

 is alleged that the little insect, known as the golden cetonia, found in con- 

 siderable numbers on rose trees, when pounded to a powder and admini- 

 stered internally, produces in the person a sound sleep, which lasts some- 

 times thirty-six hours, and which has the effect in many cases of nullifying 

 the hydrophobia affection. The oil beetle (Meloe proscarabeus) exudes a 

 deep yellow oil from the joints of the legs, which is esteemed diuretic, and 

 is used in rheumatic complaints. It has also been recommended in hydro- 

 phobia. A sour liquor which ants eject when irritated, termed formic acid, 

 was formerly obtained by bruising the red ants and distilling them mixed 

 with water ; a peculiar volatile acid passed over. This acid decomposes the 

 salts of a few metals. Silver is readily thrown out in the state of bright 

 metal on glass surfaces by means of formic acid. An analogous acid is 

 artificially obtained by distilling tartaric and sulphuric acid with peroxide 

 of manganese and water. 



The Deekamalli resin (Canarese), Teekamullya (Tamil) of India, is said 

 to be formed like lac by the punctures of insects on the branches of Gardenia 

 lucida, Roxburgh, a tree found in the Coorg jungles and other places. It 

 has a most disagreeable odour. Powdered, or made into an ointment, with 



