Where structuraTdefects cannot be corrected, soil treatments against termites may be used. A detailed description of testing such soil poisons is given. Preliminary results at Beltsville, Md., indicate that lead arsenate, Na arsenite, Na fluosilicate, cryolite, and trichlorobenzene alone and in combination with 5% pentachloro-phenol, show promise. DDT may have some effect. At Barro Colorado, Canal Zone, Na arsenite is the only promising material. Thoroughness of treatment is very necessary.