572 Shoi't Communications. 



(as more than one are engaged in the work), as well as, per- 

 haps, that of" all other insects. 



Ruminating on the subject, I am more and more impressed 

 with the necessity that some exertions should be made, and 

 experiments set on foot, to ascertain whether it be the essen- 

 tial qualities or rigidity of the membranous structure of such 

 plants as the ivy which renders them noxious or uninviting 

 to predaceous insects or other animals, as snails, &c. 



In such investigation, the chemist might be invoked to 

 render assistance. To detect by analysis the chemical prin- 

 ciples ; to ascertain by solution, expression, decoction, or 

 other means, the peculiar qualities of the invulnerable plants 

 alluded to, would be a necessary preliminary; next, the faci- 

 lity of application ; and, lastly, the effects of the application. 

 Such experimentising may be deemed a prostration of science ; 

 but, if the preservation of the beauty and usefulness of plants 

 be not an object worth the chemist's care, I know not (except 

 human life and health) what is. I may, moreover, add, that, 

 if there be any one thing more than another that deserves the 

 gardener's utmost thought and exertion, it is the most suc- 

 cessful mode of preventing the depredations of insects on his 

 crops. 



Whatever quality may be hit upon, whether vegetable or 

 mineral (for some of the latter may be found most efficient), 

 as a safeguard of plants, it ought to be administrable as an 

 ablution or wash : as such, the garden-engine or syringe 

 might be employed with ease, and with little loss of time. 

 The best season to apply any such wash or sprinkling is cer- 

 tainly the autumn, because it is then that the eggs of insects 

 are laid on the bark of trees on which they breed. Another 

 sprinkling or two in spring (one before, and the next just 

 after, the buds have burst) will go far to annoy and disperse 

 the larvae. 



These remarks I take the liberty to send you, because they 

 may induce some of those, whether chemists or gardeners, 

 who have opportunities, to pursue the subject ; as it may turn 

 out that some of our most bland and even sugary vegetable 

 substances may prove a complete defence against the attacks 

 of various insects. I am, Sir, yours, &c. — J. Main. Chel- 

 sea, July 9. 1833. 



\^oot destroys or drives off from all Plants of the Cabbage 

 Tribe, from Tinks, and from other Plaiits, those common and 

 voracious Grtcbs of Gardens, the LarvcE of the Moths of the 

 Family ^octuadce.'] — After being annoyed, almost to despair, 

 by the ravages of this grub, I resorted to the use of soot, and 

 thus applied it : — 1 laid it dry, and near an inch thick over the 



