INSECTICIDE STUDIES. 



I. PYRETHRUM POWDERS roXTAIMNi; I'nlSoNors MKTALS. 



INTRODUCTION. 



In the course of a recent examination of a large number of miscel- 

 laneous insecticides it was observed that a number of pyrethrum 

 powders contained lead chromate. Those powders arc .sold under 

 such names as Persian Insect Powder, Dalmatian Insect Powder, 

 Buhach, and Pyrethrum, and are colored yellow because there seems 

 to be a popular demand for this grade of goods, the public apparently 

 believing that the preparation must he bright yellow in order to 

 kill insecN. As a matter of fact pure pyrethrum, which is composed 

 of the ground flower heads of Pyrrflu'mn rosewm and J'yrethrum 

 cinerariasfolium^ usually possesses a light yellow color, but never 

 the brio-ht. intense yellow color given to it by lead chromato. 



As lead chromato is known to be poisonous, it would appear that it 

 i* a very reprehensible practice to add it to pyrethrum powders, since 

 they are often blown about living rooms with a bellows to kill insects, 

 and are consequently inhaled by human beings. Besides this, pvro- 

 thrum is always advertised to be harmless to human beings, which it 

 is when pure, but ceases to be so when it has been mixed with lead 

 chromato or other yellow colored chromates. In view of the above 

 facts it was deemed advisable to examine the py roth rum powders sold 

 upon the American market to discover which of them contain yellow 

 chromates and at the same time to cite eases of poisoning by chromates 

 to substantiate the claim that any of the yellow chromates that might 

 be used for this purpose, and especially lead chromato. are poisonous 

 to human beings. The facts which have been collected on these points 

 are embodied in the following report: 



CASES OF POISONING BY LEAD AND OTHER CHROMATES. 



Since it is not generally known that many pyrethrum powders con- 

 tain lead chroma te, it doubtless often happens that physicians are 

 much puzzled as to the cause of the illness of persons who have been 

 exposed to the action of such powders. In order, therefore, that 

 physicians and others may recognize the symptoms of chromate 



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