191 



two f oUowing rough approximations were found exceedingly useful : 

 area of circle = |D- (D = diameter) ; one ounce of cresol to 100 

 cubic feet of water gives a dilution of 1 in 100,000. Experience 

 confirmed Mayne's conclusions [R.A.E., B, viii, 90] that cresol 

 does not spoil the water for animals or vegetable gardens. Reasoning 

 from the life-history of the mosquito, the cresol solution should be 

 added at intervals of from 7 to 10 days. In actual practice treatment 

 was carried out twice a week. For small ponds the cresol is simply 

 stirred in with sticks ; for large ones, a board lying flat on the water 

 steadied by a keel, and held by drag-ropes, can be puUed forwards 

 and backwards ; in streams the solution can be spread with a brush. 

 Cresol is useless for drip-cans. 



Decoy-pools, if carefully constructed and accurately treated with 

 cresol in a 1 to 100,000 solution, were exceedingly effective. The only 

 difficulty is to make the pools attractive to the mosquito, and in some 

 instances all devices to induce oviposition were unsuccessful. A 

 combination of constructional and larvicidal methods was generally 

 used in the case of streams and pools. Three types of sprayer were in 

 use : Mackenzie, Special Rapid, and Vermorel. The first-named M^as 

 the best, its only real drawback being its tendency to become clogged, 

 but this may be prevented by always washing out after use with 

 cresol. For clearing, short-handled bill-hooks are the best. 



The importance of trained supervisors is emphasised ; for practical 

 purposes a short course of five or six lectures with practical demon- 

 strations proved sufficient. 



Du ToiT (P. J.). Gastruslarven und infektiose Anamie der Pferde. 



[Bots and Equine Infectious Anaemia.] — Monafshefte f. praktische 

 Tierheilhmde, xxx, 1919, p. 97. (Abstract in ScJnveizer Arch, 

 f. Tierheilk., ZiiricJi, Ixii, no. 1, January 1920, pp. 34-35.) 



The typical reaction shown by a horse after injection with a watery 

 extract of bot [GastropJiilus] larvae is regarded by the author as toxic 

 in nature, and not anaphylactic. Repeated injections caused a 

 gradual intoxication, as shown by loss of condition, decrease in the 

 number of red blood corpuscles and dullness, but the febrile attacks, 

 as in infectious anaemia, never occurred. From numerous experiments 

 the author concludes that there is no relation between bots and in- 

 fectious anaemia. 



Todd (J. L.). |Concerning Immunity to Human Trypanosomiasis. 



— Neiv Orleans Med. & Surg. Jl., Neiv Orleans, Ixxii, no. 5, Novem- 

 ber 1919, pp. 293-295. 



There is no history or tradition of a time when trypanosomiasis 

 was not endemic and universal in the Gambia. In 1911 about 0"8 

 per cent, of the population was infected ; Glossina palpalis and G. 

 morsitans are widely distributed, and are often very numerous. The 

 natives' manner of living does not particularly expose them to bites ; 

 their villages, grazing grounds and farms are usually at some distance 

 from the water. They are prosperous and well able to resist disease. 

 The method of searching for trypanosomiasis was such that cases 

 doubtless are missed. None the less these factors are not sufficient 



