340 JOURNAIv OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. 14 



sensation peculiar to that organ. The capsaicin series is highly 

 irritating to all cells. Perhaps the sensation of pungency is only the 

 effect of the irritation of specific cells on the tongue. 



The type of reasoning and of investigation above discussed has been 

 used only recently to produce new repellants for insects, to combat 

 human parasites. Moore and Hirschfelder^° have made such a study 

 upon the body louse and have demonstrated that the impregnation 

 of the garments with certain halogenated cresols will repel this parasite 

 for considerable periods. It would seem that here is a wide field for 

 work. Research similar to that of Moore and Hirschfelder should 

 lead to the discovery of repellants for such pests as black-flies and 

 mosquitoes, a boon not merely to those who frequent the swampy 

 lands of our continent but also to those who live in malarial regions. 



While Moore and Hirschfelder and a few others have made a be- 

 ginning in this sort of research in relation to insects troublesome 

 to man, but little work has been done to improve or devise better 

 insecticides and fungicides useful in agriculture. The economic 

 losses from insect and fungous ravages are enormous. Despite such 

 losses we have been content with relatively few simple insecticides and 

 fungicides. The organic insecticides in present use are largely natural 

 plant substances such as the poisons of the hellebore and larkspur, 

 pyrethrum, and nicotine from the tobacco plant. In addition, cyan- 

 ides, long known to be poisonous, and mineral oil emulsions are also 

 used. Recently the employment of certain war gases has been ad- 

 vocated. Of the inorganic insecticides, arsenates, known for centuries 

 to be poisonous to higher animals, and lime and sulfur sprays represent 

 obvious and readily available substances. The use of fluorides 

 represents a rather distinct and valuable discovery. No really 

 synthetic organic substance has come into use as an insecticide. It 

 is evident that the range of our insecticide and fungicide armamen- 

 tarium at the present time is very narrows There is no reason why 

 this range could not be extended vastly by the development of a sister 

 science to chemo-therapy, a science for which I venture to propose 

 the name chemo-phy to- therapy. The aim of chemo-phyto-therapy 

 would be to protect plants from the attacks of microorganisms and 

 insects just as the aim of chemo-therapy is to protect animals from 

 such attacks. As chemo-therapy demands the working together of 

 pharmacologists and chemists, so chemo-phyto-therapy would demand 



^0 W. Moore and A. D. Hirschfelder. An investigation of the louse problem. Re- 

 search Publ. Univ. Minnesota 8: No. 4. July, 1919. 



