There are certain preparations made from coal-tar which, either alone or combined with carbolic acid, have very strong disinfecting properties and which are the bases of most of the patented disinfecting solutions now sold. They are commonly called cresols or creosols and a 4 per cent solution of any of the three ordinary forms will destroy bacteria in a few hours. They are commonly used for receiving organic excretions of sick persons in the same way as carbolic acid is used, and have about three times the power of carbolic acid to destroy bacteria. They have one great advantage besides the strength mentioned, in that they are not materially affected or interfered with by the presence of albuminous material. Carbolic acid in the presence of albuminous material, like sputum, for instance, has the strength of the disinfectant partly used up in combining with this albuminous material so that the strength remaining for disinfection is weakened, and the result is not as satisfactory as it would otherwise be. The coal-tar products, on the other hand, are not so interfered with, and the solution acts in full strength upon the bacteria. _Mercury for disinfectant._ Corrosive sublimate, or bichloride of mercury, is one of the most active poisons known and is as effective in dealing with the microscopic organisms known as bacteria as it is in dealing with the larger animals for which it has been used for years past,--the destruction of bed-bugs. For general cleaning purposes, such as scrubbing woodwork, floors, and walls, it should be used in strength of about 1 part to 3000 parts of water. This means that for 1 ounce of corrosive sublimate 3000 ounces of water or 25 gallons must be taken. This solution is very active in its effect on all metal, so that it must be kept in brassware or earthenware, and when mixed with the material which it is intended to disinfect, it must be kept from tin or iron. This solution is also affected by albuminous material, although this may be counteracted by the addition of salt. It is a good plan, therefore, to add to the solution salt at the rate of about 4 teaspoonfuls to each gallon of solution. On account of the very poisonous action of this solution great care must be taken to keep it away from children, and it has been suggested that it is desirable to add some coloring matter to the liquid, since without this it may be mistaken for clear water. _Lime for disinfecting._