“He had been woodcarting in the bush for a considerable time, and while thus engaged eight weeks before admission began to lose power in his left arm and leg; gradually the paralysis increased, and he was taken home, where he remained for six weeks. During this time he had every week an attack of severe headache, and once he lost all sight for over half an hour. Gradually the symptoms increased, and he was taken to the hospital, but even then was able to walk with assistance part of the way. “At the autopsy, when the calvarium was removed, a large cyst about four inches in diameter was found on the mid-convexity of the right hemisphere of the cerebrum, slightly towards its anterior part. It formed a marked prominence on the anterior surface of the brain, and was bounded superficially by the pia mater and arachnoid, which were neither noticeably thickened nor adherent to the dura mater. On opening the cyst it was seen to extend inwards and abut on the wall of the lateral ventricle, and consisted of the ordinary gelatinous membrane, studded internally with little granular eminences, some pellucid, some opaque white. The contents were thin limpid fluid. The brain tissues around presented scarcely any induration. All other organs structurally healthy, congestion being the only morbid condition present. “The specimen is preserved in the hospital museum, which contains two other preparations of hydatids in the brain, and also an hydatid cyst of large size growing from the interior of the frontal bone.” In concluding this account of hydatids I may remark that, by the employment of sanitary measures, the disorder might, in course of time, be thoroughly stamped out. What these measures are I have already stated. I need hardly say that the following bibliography by no means exhausts the records of echinococcus disease. In Dr Albert Neisser’s recent monograph nearly a thousand separate cases are quoted and classified. The monograph of Dr Hearn, which is not mentioned in Neisser’s work, also contains a valuable bibliography.