successful large scale experiments referred to in the last report (L.P.(43)223) some 3,540 miles of London sewers the occupation of the London County Council and 44 Metropolitan and adjacent Authorities have been treated under Direction. The result were most satisfactory, not only to the Ministry but, also, to the Local Authorities themselves, who will be advised to maintain treat ###t at fixed intervals. The number of manholes treated was over 38,000. In the process, 29 tons of bait material and nearly 21/2 tons of pois### were used.