TREATMENT of general paralysis of the insane by means of induced malaria, commenced in 1917, has been adopted everywhere. In the early days of malaria therapy, the fever was induced by the injection of the infected blood of a malaria patient, and this is still occasionally done; but generally the fever is now transmitted through the bites of infected mosquitos. This has been rendered possible by the establishment of a 'mosquito farm' at the Horton Mental Hospital. Full details respecting this 'mosquito farm', and of the methods employed for breeding, infecting and transmission are given in a recently issued report by Lieut.-Colonel J. A. Sinton ("A Report on the Provision and Distribution of Infective Material for the Practice of Malaria-Therapy in England and Wales". Reports on Pub. Health and Med. Subjects, No. 84. London: H.M. Stationery Office. 6d. net). At Horton, in a special insectary, an indigenous species of mosquito, Anopheles maculi-pennis, var. atroparvus, is bred throughout the year, freshly hatched females are collected and are stored in cages in an outhouse, being allowed to feed on a rabbit at appropriate intervals. When required for transmission Work, the insects are placed in a special hot room for 48 hours, and are then allowed to feed upon a suitable patient with malaria in the wards of the hospital. A special Madagascar strain of benign tertian malaria parasite, P. vivax, is that used. A batch of 100-200 mosquitos are allowed to feed on the selected case, the insects being placed in jars and applied to the thigh of the patient. When most of the mosquitos seem to have fed, the jars are removed and the insects are then released into a storage cage, which is kept in a hot room maintained at about 75° F., and are fed every second day on a rabbit. After 10 days or so, when parasites are found in the salivary glands of the insects, the mosquitos are ready for use for transmission ; they remain active for about a month. For the transmission to a patient for the 'cure', about 15-20 infected insects are placed in jars, and are taken to the hospital where the patient is. The mosquitos are then given an opportunity of biting by applying the gauze-covered end of the feeding jar to the external surface of the patient's thigh.