46 



diverticula of the ticks were never found to harbour parasites ; (2) 

 the haemocoeHc fluid was the habitat of the early pre-flagellate forms ; 

 (3) these early pre-flagellate forms developed into full-grown Crithidia 

 in the haemocoelic fluid ; when these were present in large numbers 

 they were found to migrate to the ovarian system ; (4) the hereditary 

 infecting forms were found entering the ova ; (5) plasmodial forms 

 were found in the deposited eggs. 



Watson (Dr. M.). Mosquito Reduction and the Consequent Eradica- 

 tion of Malaria. — Trans. Soc. Trop. Med. Hi/g.. London, vii, no. 2, 

 Dec. 1913, pp. 59-82. 



A definite connection was traced in Selangor between malaria and 

 its carrier, Anopheles vmbrosus, which breeds in stagnant pools in the 

 jungle. Drainage was commenced and has resulted in the disappear- 

 ance of malaria over many acres of land. Not only was malaria found 

 to be connected with jungle pools on low, flat, coastal lands, but it was 

 also intense in the hill lands where there were no swamps and where 

 the water was perfectly clear. Here malaria is carried by a mosquito 

 called by the author at that time N. wUlmori (properly^, macidatus), 

 which breeds in clear streams. Again drainage was resorted to and 

 the percentage of cases was lowered. In the flat open land in Krian, 

 where the irrigation water came from an artificial reservoir, in which 

 dead jungle trees still stood, four species of Anopheles were present — 

 rossi, kochi, sinensis and barbirostris ; but the rice-fields were practi- 

 cally free from malaria. In the large open valleys, in addition to the 

 four Anopheles found in Krian, three others were present at Bukit 

 Gantang, namely, umhrosiis, nivipes and albirostris, all of which carry 

 malaria ; and here there was much malaria present. A. nmculatus 

 was found on the hills at the side of the valley. Investigations 

 for means of reducing the number of mosquitos are being carried out. 

 The distribution of malaria in India is very similar to that in the Malay 

 States. In India, A. macidatus is the commonest Anopheles and occurs 

 in the Duars and the Jeypore hills ; it has been reported from Ceylon 

 and has been found in a Dutch island oft' Singapore and also in Hong 

 Kong, and wherever this species is found malaria is severe. In Italy, 

 where there was only a pool-breeding Anopheles, the hills were free 

 from malaria, and where open drainiage was possible malaria could 

 be eradicated. 



The questions then arise : Is it possible that throughout the tropics 

 one would always find a hill stream-breeder and intense malaria ; 

 and are all pool-breeders as amenable to open drainage as A. umbrosa 

 on the flat land of the Malay States 1 For further investigations visits 

 were made to Sumatra, Panama, British Guiana and Barbados. In 

 Sumatra the absence of malaria is very extraordinary, and so far 

 A. maculatns has not been taken there. There was some evidence of 

 malaria near an island swamp, but no trace of it in the hill land. In 

 Panama, drainage was the most important measure against Anopheles 

 and oiling was resorted to w^here drainage was impracticable ; while 

 the success was at first due to protection from bites as much as to 

 Anojjheles reduction, the latter measure has become the more important. 

 Here the chief Anopheles are albimanvs and argyro(arsis, the former 

 breeding in almost any pool, but not in running water. British Guiana 



