OF all the pests from which the pastoral industry in Australia has suffered, rabbit infestation is prob ably the most serious economically, and little per manent success seems to follow the methods of control in use at present, such as trapping and poisoning. One hope would appear to lie in the discovery of some infectious disease, deadly to the rabbit but innocuous to man and other animals, and easily communicable to, and spreading widely by natural means among, the rabbits. Sir Charles Martin, as a result of an experimental inquiry, suggests that a disease ‘rabbit myxomatosis’ may fulfil these requirements (Commonwealth of Australia. Council for Scientific and Industrial Research, Bull. No. 96. Melbourne, 1936). This is an infectious, highly fatal, febrile disease caused by an ultra-microscopic virus, causing mucinous discharges, swellings and tumours in affected animals, fatal within twelve days or so, transmitted sufficiently by contact, and with a fatality of almost a hundred per cent. It attacks animals of the genus Oryctolagus, to which wild rabbits in Europe and Australia, and domesticated rabbits in Europe and America, belong; but it does not affect the indigenous rabbits of America, or man and other animals and birds. Experiments were conducted by Sir Charles Martin in a pen measuring 50 yards x 10 yards, with both tame and wild rabbits. A colony having been established for three weeks or thereabouts, one or two rabbits inoculated with the disease were introduced. With colonies of 27 and 30 tame, and 55 and 44 wild, rabbits, the fatality was 99-6 per cent among the tame, and 100 per cent among the wild. The disease originally came from epizootics among tame rabbits in South America.