The mechanical conveyance of germs by flies and other insects is of importance not only to the sanitary officer, but to the agriculturist and even to the merchant, for the more the matter is enquired into, the more numerous become the cases in which the origin of fermentation or disease in plants and animals can be traced primarily to this agency. Whatever may be the significance of this question in temperate climates, it is obviously of far greater importance in the tropics, where insects are present in greater profusion throughout all seasons of the year. The subject certainly merits more attention than has yet been bestowed upon it.