221 



Caballero (A.). Las Especies del G6nero Char a y las Larvas de los 



Mosquitos. — Andes Inst. Gen. y Tec. de Valencia, Trab. Lab. 

 Hidrobiol. Esp., no. 10, 1920, 17 pp. 



An abstract of this paper on the noxious effects of Char a spp. on 

 mosquito larvae has already been briefly noticed [R.A.E., B, x, 108]. 



As it was thought that a film that was present on the surface of the 

 water might be due to some exudation from the Chara that caused 

 the death of the larvae by asphyxiation, care was taken that such 

 a film should not be allowed to form on the water. The result, however, 

 was the same, and the larvae of Stegomyia died almost immediately 

 upon hatching from the Qgg, while those kept in a neighbouring tank 

 free from the alga developed in the normal way. 



The question of the quantity of the alga necessary to produce fatal 

 results can best be determined for the various species of Chara by 

 detailed observation in the field. It is thought that the alga could 

 easily and quickly be disseminated among all standing or slowly- 

 moving water (except temporary rain-pools) that forms suitable 

 breeding-places for mosquitos. The method suggested is to throw a 

 few cuttings into the pools, with something to weight them so that 

 they will, sink and can become attached to the bottom of the pool. 



Apart from the question of public health, that of the rice industry 

 has been considered, and it has been found that Chara and rice 

 can be grown together without any detriment to the rice crop. 



Zetek (J.). La Fiebre Malaria en Panama. — Rev. La Salle, Panama, 

 October 1921-February 1922, nos. 61-65, pp. 292-296, ?n?,-?ni , 

 391-399, 436-439, 5 figs. [Received 25th September 1922.] 



This is a general review of malaria as occurring in the Panama 

 Canal Zone, with an account of the parasites causing it and its trans- 

 mission by Anophelines, much of the information being taken from 

 other sources \R.A.E., B, x, 11, etc.]. 



DE Verteuil (E.). Anopheles and Malaria Control in the Brighton-La 

 Brea Rural Sanitary District, Trinidad, B.W.I. — Trans. R. Soc. 

 Trop. Med. & Hvg-, London, xvi, no. 3, 22nd June 1922, 

 pp. 99-118, 4 charts, 9 figs. 



In spite of efficient screening of houses, proper attention to the 

 drains and constant removal of grass, the rainy season in the south-west 

 ■of Trinidad has always been followed by a large increase in the number 

 of malaria cases. The locality in question is described. Further 

 measures recently instituted include the immediate and constant 

 cutting of grass within 200 yards of buildings. All drains within the 

 same range were brushed, cleaned and graded, and any other breeding- 

 places were filled in or drained. The sides of all these drains were 

 burned with a mixture of crude oil and distillate by means of an 

 ordinary hand-pump spray such as was used extensively in Panama. 

 The grass was thus checked for a period of about three months. 

 All pools and collections of stagnant water were sprayed with crude 

 oil. Within five or six weeks the satisfactory results of these measures 

 were evident, as very few Anophelines were to be found. Their 

 effect could, however, only be temporary and they required a large and 

 recurrent expenditure. In 1921 the drains were lined with a hard 

 waterproof lining of asphalt and sand ; this prevents the growth of 



(82620 Wt.P.6/200 1500 12/22 Harrow G.75 S 



