1. A method for the preparation of 8 to 10 liter quantities of T2 virus lysates, titering 2 to 5 x 1011 infectious units per ml. has been described.
2. Procedures have been developed for the concentration and purification of virus to a high specific infectivity. No fractionation procedure of the several used succeeded in further raising the specific infectivity of these purified preparations.
3. Some of the general properties of the better preparations have been determined. They exhibited titers of 2 x 1015 infective units per gm. of material or 1.2 x 1016 per gm. of nitrogen.
4. A study of the distribution of nitrogen among the various fractions of the virus showed that about 6 per cent of the total nitrogen is soluble in 4 per cent trichloracetic acid; that the protein nitrogen is about 40 per cent of the total and the nucleic acid nitrogen is 53 per cent. At least 96 per cent of the total phosphorus is in the nucleic acid fraction. Less than 0.5 per cent quantities of lipid and PNA were found.