He was under the care of Mr Luke (1834). Comparatively recently I inspected the collection at St Thomas’s Hospital, which I found to be particularly rich in entozoa of various kinds, especially tapeworms and hydatids. I encountered seventy-six preparations of internal parasites; and of these, forty-two were of the hydatid kind, representing at least thirty-three different cases. I say “at least,” because it is often impossible to decide in instances where no history of the specimens can be obtained. Thus, there are three similar preparations of hydatids passed by the urethra, and, from their appearance, I judge them to have come from one and the same patient; yet there is no statement in the catalogue to that effect. Of the thirty-three cases of hydatids represented in this museum, I reckoned eighteen as referable to the liver, two to the brain, two to the bones, two to the urinary organs, and one to the lung, spleen, uterus, and soft parts of the thigh respectively. There are also three that may be classed as peritoneal. There is another choice example in which the disease cannot be referred to any particular organ. I allude to Dr Peacock’s case, already published (‘Pathological Transactions,’ vol. xv), where the lungs, liver, heart, spleen, and some other organs, were all occupied by hydatid formations. As an instance of extensive visceral infection by Echinococci in the human subject, I believe this case to be unique. The brain hydatids are particularly fine. In the specimen presented by Mr Boot, of Lincoln, the hydatid, two inches in diameter, is lodged in the anterior horn of the left ventricle. One of the peritoneal cases is remarkable for the amount of forward displacement of the pelvic viscera, caused by four or more hydatids, each of them nearly as large as a cricket-ball. Amongst the abdominal cases I have included a recent preparation, to which Mr Stewart has called my attention. The hydatid in question, of the size of a large lemon, existed near the fundus of the bladder, its walls being one third of an inch in thickness, and forming an unusually firm tumour. Of all the fine specimens of hydatids in the collection, however, none have struck me so much as those affecting the bones. There is a humerus, taken from a man thirty-four years of age, in which the shaft is occupied throughout by small hydatids that have destroyed almost all the cancellous structure; in some places, also, the absorption of the cortical layer has gone on to such an extent as to have left little more than the periosteum. Of course, the bone was at last fractured easily. It is a beautiful specimen; and the existence of Echinococcus-heads was proved by microscopic evidence. Scarcely less interesting are two preparations illustrative of Mr Traver’s case of a man, thirty-eight years of age, in whom numerous small hydatids occupied both the head of the tibia and the lower end of the femur. Each set of parasites freely