138 Kansas Academy of Science. 



INSECTICIDES. 



By L. E. Sayre. 



SINCE the enactment of the food and drugs law there has been 

 a tendency toward standardization of all substances in any 

 way allied to drugs and poisons, as well as of foods and food acces- 

 sories. The federal insecticide regulation No. 16 requires the in- 

 gredients of insecticides to be disclosed when containing arsenic 

 or any of its combinations. 



Insecticides, other than arsenical combinations, and fungicides 

 containing inert substances which do not prevent, destroy, repel 

 or mitigate insects or fungi, must bear a statement on the label of 

 the name and percentage of each inert substance therein, unless 

 the name and percentage of each active ingredient of the article is 

 plainly and correctly stated, in which case it will be sufficient to 

 state on the label that the article contains inert substances, giving 

 correct percentage thereof. 



Our knowledge of insecticides and fumigants up to recent times 

 has been very inaccurate. Investigators having been drawn to the 

 subject by the attitude occasioned by the federal and state regula- 

 tions, more accurate information concerning them is now possible. 



In the Journal of the American Public Health Association, 1911, 

 there is a valuable contribution to our knowledge of insecticides 

 by McClintock, Hamilton, and Lowe. They have in this article 

 ably discussed the subject, and have shown the results of their in- 

 vestigation, giving the relative value or cofficients of the popular 

 toxic agents employed for the extermination of insect pests. An 

 ingenuous apparatus has been devised by them, a rough diagram 

 of which is here reproduced. 



This apparatus is so constructed as to make possible the meas- 

 uring of definite amounts of gases, which may be drawn from a 

 container for any experiment. Such gases as illuminating gas. sul- 

 phur dioxide, carbon dioxide, hydrogen sulphide, etc., have been 

 employed. Insects confined within the glass chamber of the ap- 

 paratus and subjected to the influence of various insecticides can 

 be watched and timed, so that the relative value of toxic action can 

 be readily estimated. The insects experimented upon by the above 

 investigators were bedbugs, cockroaches, house flies, clothes moths, 

 and mosquitos. It was found that the minimum quantity neces- 

 sary to kill the insects varied, of course, according to the toxic 



