Dr. Cartwright of Natchez, attributes the exemption of some districts of Louisiana from malarial fevers to the abundance of this pretty, creeping aquatic plant. We feel bound, as news-gatherers, to record this piece, because it will no doubt have wide currency, but have to confess that we see no other ground for the doctor's opinion than because it so happens that this plant grows there. Probably hundreds of other plants are abundant there as this; and even then the abundance is no proof of value.