A very peculiar case of poisoning, caused by plant exhalation, having occurred at these gardens, it is desirable that it should be recorded, not alone for general information, but more especially as it is possible that the plant in question may, to a limited extent, be under cultivation in other places. Before describing the case, a few general observations relative to the matter may not be out of place. The genus Rhus embraces numerous species, many of which produce gums and resins used in the manufacture of superior kinds of varnish and some are esteetned for the preparation of leather, while not a few of the species are poisonous to a greater or less degree. The plant is common in North America, where it is known as poison ivy. The particular plant in question has been in the garden for many years. It is very probable that the plant may have a more poisonous influence at one season than another, and to this I am inclined to ascribe its effects in the present case, when six persons became poisoned by it at one time, two at least to a serious extent. Symptoms varied slightly between those affected.