Fleas and Disinfectants

The important part that fleas acd flies and mosquitoes and other small insects play in the spread of infectious diseases and complaints such as plague, enteric, typhus, malaria and summer diarrhoea is becoming more generally recognised every day ; indeed Sir Lauder Brunton speaks of fleas as a national danger (Tha Lancet, Nov. 9th, 1907), and the destruction of these insects is a problem which has now to be seriously faced. The germ theory of disease has resulted in the production of large quantities of reliable disinfectants and germicides, which can be purchased practically all over the world at very moderate cost. It is far otherwise with the reliable insecticides, for while there are a few which may be relied upon to kill certain insects, there are a largo numbor which arc absolutely usoless for any purpose. There is at the present time a real need for a reliable substance which will combine good disinfecting properties with a high insecticidal value, for it is obviously inconvenient and expensive when carrying out preventive measures to have to apply two solutions or two gases. The ideal liquid disinfectant-insecticide of the future must be one which has a sufficiently high germicidal value and be capable at the same time of killing both soft and hard shelled insects. The disinfectant should be cheap, non-poisonous, (to man and domestic animals), non-corrosive, non-inflammable, and mix readily with water. The search for such a liquid has caused considerable attention to be given to the action of disinfectants on rat fleas in India. Dr. W. Uossack in 1906 {Indian Medical Gazette, Vol. XLI, No. 7, July 1906) made some experiments which he carried out as follows:?