118 



Sardinian towns of Algliero and Terranova Pausania. After a careful 

 survey of the breeding places of Anopheline mosquitos, complete anti- 

 larval work was carried out, supplemented by drainage restricted to 

 those waters which had proved to be a source of danger. The work 

 began in September 1915, and cost only £140, whereas over £80,000 

 had previously been spent at Terranova alone. Of 400 children born 

 between 1st November 1915 and 31st October 1916, only three 

 became infected with malaria, and these had been removed from the 

 protected region. 



Petroleum should be applied twice a month at the rate of 20 c.c. per 

 square metre of water surface. It causes but little inconvenience as 

 the heat evaporates it within 3-5 days. The roots of vegetables will 

 not be injured by irrigation with water from oiled places, as the water 

 is drawn off under the surface and the minute quantity of petroleum 

 which may reach the plants will evaporate before reaching the roots. 

 The alga, Lenina palustris, provides an easy means of covering a 

 surface of water where petroleum cannot be used. To sow this is a 

 simple matter, a complete covering being ensured in 3-4 weeks by 

 throwing in a handful for every 10 square metres. Wells may be 

 protected by using a little over 2 lb. of cork granules of no. 3-4 size 

 per square metre of surface. When drawing water, it is only necessary 

 to strike the surface two or three times with the bottom of the bucket 

 in order temporarily to displace the covering. 



Arkell (T. R.). Get rid of the Ticks. — Agric. Jl. Dept. Agric, 

 Victoria, B.C., ii, no. 3, May 1917, pp. 47 and 51, 1 fig. [Received 

 15th June 1917.] 



The mite [Psoroptes communis] causes sheep-scab, a contagious 

 disease, governed by the " Animal (Contagious Diseases) Act," under 

 which failure to report an outbreak involves a fine of £40. Clipping 

 the wool from the affected part and dipping twice at an interval of 

 10 days effects an almost certain cure. The sheep louse [Trichodectes 

 sphaerocephalus] and the sheep tick [Melophagus ovinus] also cause 

 disease, and it is against the attacks of the latter Hippoboscid fly that 

 dipping operations are chiefly directed. The mistake is frequently 

 made of dipping only once, i.e., in the spring after shearing, when the 

 insects are visible, though in reality it is, if anything, less necessary 

 then, when many would naturally die from sudden exposure to the 

 cold, than in autumn when the fleece is heavy. Further, if sheep are 

 heavily infested during the winter, when both food and weather 

 conditions lower their vitality, they lose flesh and become debilitated. 

 Dips containing carbolic acid, arsenic or tobacco, and most proprietary 

 dips, give good results if the directions are carefully followed. For 

 autumn dipping it is advisable to construct a draining-pen, or better 

 still, two in connection, close to the dipping tank to prevent the waste 

 of a large quantity of dip soaked up by the long wool. The operation 

 should be performed on a bright sunny day, and the dip should bf 

 warmed to about 100°, as the sheep should be kept in it for not les: 

 than two minutes. 



