IN a Circular (No. 1563. Price Id. net) and accompanying Memorandum (Memo. 199. Med. Price 2d. net. London: H.M. Stationery Office) issued to county, and county borough, councils, the Minister of Health directs attention to the responsibility and risk attached to the use of imperfectly sterilized, or unsterile, catgut for surgical purposes. Several groups of cases of tetanus infection have recently occurred following surgical operations in which catgut had been employed, in some of which the infection was definitely traced to the catgut. Under the Therapeutic Substances Act, 1925, and Regulations, 1931, the manufacture for sale and the importation of sterilized surgical ligatures and sutures is prohibited except under licence from the Minister of Health, and the granting of such licence is conditional upon routine testing of samples of the product for sterility, and upon control and inspection of the process of manufacture. When ‘sterilized surgical catgut’ is employed, the patient may be regarded as adequately safeguarded from tetanus infection, but in many hospitals ‘raw’ unsterile catgut is bought for use. Such catgut is not controlled under the Therapeutic Substances Act, and is ‘sterilized’ in the hospital itself by a process which may or may not be satisfactory. The Memorandum describes the method of preparation and of sterilization of catgut. Respecting the sterilization process, heat is sometimes employed, but needs great care, and an aqueous solution of iodine, with or without preliminary treatment with hydrogen peroxide, is efficient and widely used. Most other sterilizing agents are inefficient, or damage the gut.