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Theo. ; A. {M.) funestus var. arabica, Christophers, and A. {Pyreto- 

 phorus) cinereus, Theo. Ticks, fleas, and lice occurred in small numbers. 

 A. culicifacies was found to breed freely in surface water collections 

 and in shallow wells between October and March inclusive. Adults 

 were taken in the vicinity of the camp in small numbers from November 

 1914 to February 1915. Larvae of A. stephensi were present in two 

 situations, one a cistern, the other a brackish pool, between October 

 and December 1915 ; no adults were observed. A. rhodesiensis was 

 present in abundance in pools of surface water during March 1915. 

 Breeding was rapid until the first half of May, then decreased in 

 activity until October. During that month larvae were fomid in 

 wells in small numbers. Adults were taken in Muscat Fort in March 

 and April. This species probably attacks man. A. funestus var. 

 arabica was confined to underground aqueducts, in which situations 

 larvae were fairly numerous between November and April. Adults 

 were captured from November to January ; they appeared to rest 

 during the day on the sides of the aqueducts immediately above the 

 breeding places. Larvae of A. cinereus were present in a tank in Muscat 

 during December. The breeding places of Anophelines were thus 

 mainly of a permanent character, and breeding was continuous 

 throughout the year, except during the hottest months. 



An examination of civil and military fever statistics showed that a 

 marked decline in malaria occurred in June, and few cases were observed 

 between this month and September. During this period high tempera- 

 tures and a high degree of humidity prevailed. Malaria was very pre- 

 valent in April and May, when a high temperature was accompanied by 

 a relatively low humidity. Although Anophelines were present almost 

 throughout the year, their numbers were scarcely enough to bring 

 about a rapid spread of the disease. The evidence collected in 1915 

 seemed to show that the majority of cases of fever among the troops 

 were relapses due to previously acquired infection. The civil popu- 

 lation however showed a high degree of infection, and it must therefore 

 be assumed that active transmission of the disease may occur in certain 

 years. The tendency to relapse may be occasioned to a greater or less 

 extent by the climatic and physiographical conditions. Cases of 

 blackwater fever occurred among the civil population throughout the 

 greater part of the year ; the disease was associated with intense 

 malaria and chiefly affected indigenous inhabitants and old residents. 



Anti-malarial measures were almost entirely neglected by the civilians 

 of Muscat. The following recommendations are made : — ( 1) extension 

 of the pipe system of water supply, thus decreasing the necessity 

 for private wells ; (2) the proper covering of wells, tanks, etc. ; (3) the 

 use of mosquito-nets throughout the year, and the screening of windows, 

 etc., with wire gauze. In the camp, the covering of wells and the filhng 

 in of a collection of surface water resulted in an appreciable decrease in 

 the numbers of mosquitos. The access of mosquitos to troops under 

 canvas could be prevented to a considerable degree by providing a 

 double screen of mosquito-netting at the door of the tent. 



The system of quinine administration is discussed. The scheme 

 consisted of the continuous use of relatively small doses for a prolonged 

 period. No attempt was made to administer the drug except to known 

 malaria cases and to those showing enlargement of the spleen. This 

 method of procedure resulted in a gradual decrease in the number of 

 cases of fever treated. 



