440 STATE BOARD OF AGRICULTURE. 



a further study of these oxydasic and reducing bodies of /*. cormctus and 

 to determine the effect of some of the contact insecticides upon their 

 activity. How, for example, would gasoline vapor or the vapor of car- 

 bon disulphide atfect the rate at which the crude water extract could 

 oxidize a solution of hydroquinone? When present in concentrated 

 amounts, the rate at which oxygen was absorbed by insects and by crude 

 insect tissue-extract was lowered by these insecticides. Would they re- 

 duce the rate at which the oxydases in the extract caused guaiac or hy- 

 droquinone to become oxidized? 



THE EFFECT OF GASOLINE AND SOME OTHER CONTACT INSECTICIDES 



UPON THE OXIDASE, CATALASE, AND REDUCTASE ACTIVITY 



IN EXTRACTS OF THE TISSUES OF P. CORNUTVS. 



(a) EFFECT UPON OXIDASIC ACTIVITY. 



It has been pointed out that both soluble and insoluble oxidases were 

 found to be present in the extract of P. cornutus. The insoluble oxidase 

 (oxydone*) remained in the mixed residue on the pressure filter after 

 filtering the crude extract, while the soluble form went through in the 

 clear or straw-colored filtrate. When the latter was treated with alco- 

 hol or saturated ^ath ammonium sulphate until the proteins were thrown 

 down, the oxidase separated with them and could be filtered out. The 

 oxidasic activity of this alcoholic or ammonium sulphate precipitate 

 could be preserved for hours or even days, if the precipitate were kept 

 moist and cool; but drying, even at room temperature, almost if not 

 entirely destroyed the activity of the oxidase in a few hours. On the 

 other hand, when the washed residue containing the oxydone was moist- 

 ened after having been dried at room temperature for 36 hours or even 

 longer, it exhibited oxidasic action toward alcoholic guaiac almost un- 

 diminished. Moreover, in the dry condition, the oxydone was very resist- 

 ant to heat. It could then be kept at 90° to 100° C. for an hour without 

 destroying all of its activity. When moist, as in the crude extract, how- 

 ever, both the oxidase and the oxydone were destroyed if kept at a boiling 

 heat for 10 minutes; and nearly all oxydasic activity was destroyed if a 

 crude extract were kept at 80° to 81° C. for 15 minutes. When kept at 

 68° to 69° C. for one hour, such an extract was 5 to 6 times longer in 

 oxidizing alcoholic guaiac than a check kept at room temperature for 

 the same time. In making this comparative test with alcoholic guaiac, 

 the same amount of extract was used for the check as for the heated 

 portion, and at the end of the test period a certain number of drops of 

 the guaiac solution were added to each portion. Then the time required 

 to oxidize the guaiac in the treated and untreated extracts to the same 

 depth of blue coloration was noted. This was a method by which only 

 well marked differences might be compared, but by its use one could 

 easily see also that solutions of hydrochloric acid, borax, sodium fluoride, 

 nicotine (to-bak-ine) and' ammonia all exerted a more or less harmful 



♦Insoluble oxydases in animal tissues are referred to as "oxydones" by Batelli, and (Mile) 

 Lina Stern. Biochem. Zeitsch. 1913, 52, p. 226. Rev. in J. of Chem. Soc. vols. 103-104 

 pt. i, p. 929. 



The work of these investigators did not come to the notice of the author until early in 

 1914, when this phase of his own work was nearly finished — having been begun in 1912. 



