The great inventor Siemens once told the writer he knew of no substance but that had its enemy, and he expected his guttapercha cables would be attacked in time. We animals - men - have a sad annoyance in the mosquito, which conquers even the most learned scientists, as we find by the proceedings of a committee of the American Association for the Advancement of Science. The members encamped at Fort Wool, Virginia, where in their own words they say, " The mosquitoes came by millions; the air was filled with them, and the noise of their busy wings sounded like an approaching storm. No one slept, that was impossible." So the scientific men gave it up and decamped.

The Canada Horticulturist prints an eulogium on "insect powder," as a great desideratum in destroying the pests of the greenhouse. When shall we have a powder to kill the human pests?