DEHATISATION 553 FOR USE OF PORT LOCAL AUTHORITY. CERTIFICATE. PORT OP ISSUE. DATE. FUMIOAKT USED Deratisation Deratisation Exemption DERATISATION. Deratisation Certificate.— The International Sanitary Convention of 1926 made it necessary for all ships to obtain from the Port Sanitary Authority a " Certificate of Deratisation," but if a ship can be shown to the satisfaction of the Port Authority to be reasonably free from rats a " Certificate of Exemption from Deratisation " will be granted. Both certificates hold good for six months. The onus of keeping the ship free from rats is thrown upon the ship. If the ship is kept free the Certificate of Exemption will be issued, if not, then fumigation will have to be undertaken. The certificate, when issued, must be kept on board the vessel with the ship's papers in order that it may be produced at every port. Unless this is done the ship will have to be inspected again with the possibility of fumigation having to be carried out. The certificate will be accepted by every country signing the Convention as evidence of the ship^being free of rats. Rats begin to breed from the age of two to three months, period of gestation three weeks, litter eight to ten rats, very prolific. It is estimated that the progeny of a pair of rats may reach the colossal total of 860 in the course of a twelvemonth. There are two species, the brown rat and the black rat. The brown species is a shore dweller and burrows; the black rat is a climber, frequents ships and is a plague carrier, the disease being transmitted to human beings by fleas. RATS AND MICE (DESTRUCTION) ACT, 1919. The attention of Ship's Master is drawn to the following provisions of the Act and requirements of the Local Authority:— PROVISIONS OF THE ACT. (1) The Bats and Mice (Destruction) Act applies to a vessel as if the vessel were land, and the Master of the vessel the occupier thereof. Section 6 (1). (2) The Local Authority may by notice served on the Master of a vessel