170 



The author criticises these conclusions and expresses the view that 

 the unicist hypothesis leads in fact to results that are inexplicable, and 

 requires a number of auxiliary hypotheses. He points out that 

 while the American settlement of Portobello (Panama) was practically 

 free from malaria (only an occasional case of benign tertian occurring 

 there), the township of the same name on the gulf suffered from disease 

 of the malignant type. As the climate was the same the presence of 

 two diseases must be assumed, of which the malignant form had been 

 eradicated in the American settlement, while the benign form occasion- 

 ally occurred there owing to its tenacity in man. Similar observations 

 will probably be multiplied wherever malaria control is energetically 

 prosecuted, and the eradication of one form at a time when the other 

 endures will definitely negative the unicist theory. The acceptance 

 of three different causal agents agiees better with existing facts. 



MoLLow (W.). Ein Malariagesetz in Bulgarien. [An Anti-Malaria 

 Law in Bulgaria.] — Arch. f. Schiffs- u. Trop.-Hyg., Leijmc, xxiv, 

 no. 5, June 1920, pp. 129-132. 



A resume is given of the a nti- malaria law passed in 1919 in Bulgaria, 

 This is based on similar legislation m Italy, Greece and Rumania, 

 one chapter dealmg with anti-mosquito measures, including extensiv^e 

 screening. 



ZupiTZA (M.). Ein Weg zu erfolgversprechender Bekampfung der 

 Schlafkrankheitsfliege am Tanganika. [A Way to combat the 

 Sleeping Sickness Fly successfully on Lake Tanganyika.] — Arch.f. 

 Schrffs- a. Trop.-Hyg., Leipsic, xxiv, no. G, June 1920, pp. 161-166. 

 [Received 3rd August 1920.] 



When in 1914 the author visited the sleeping-sickness area in the 

 Tanganyika-Russisi region, the measures adopted there had prevented 

 the spread of the disease, but its ultimate suppression was endangered 

 by the unsolved problem of Glossina control. 



The entire eastern shore of Lake Tanganyika is exposed to infestation 

 by fly from the marshes on both banks of the Russisi. 



The whole area is now under the administration of the Belgian Congo, 

 and anti-Glossina work must be resumed. The key to successful fly- 

 control is to be found on the western bank, where the only outlet from 

 the lake, the Lukuga river, is to be fomid. About 2| miles from the 

 lake this river flows through a rocky gorge, the width and depth of 

 which determines the average water-level of the lake. By widening 

 and deepening this passage the level will be artificially lowered, thus 

 draining both the marshes and the sub-soil water in depressions along 

 the banks. This will destroy the reeds and other aquatic plants and 

 dry the air, so that conditions will become unfavourable to the fly. 

 The low level of the lake will quicken the current in the lower reaches 

 of all its tributaries, and this will clear their beds and drain the sub-soil 

 water around them. 



The disadvantages of this plan include the possible formation of 

 fresh depressions in the reclaimed areas, and the reconstruction of the 

 wharves and of the terminal portions of the railways leading to the lake. 



This suggestion is advanced in the interests of the native population, 

 and it is hoped that it will be subjected to careful consideration. 



