464 STATE BOARD OF AGRICULTURE. 



a test by the heat-treated extract to that liberated by its check was 

 1 = 0.87. 



Some of the agents readily showed a slight acceleration of the catalase 

 action, when used in small amounts. Attention may be called to gas- 

 oline and alcohol in the table (V) as illustrating this fact. The manner 

 in which some of the insecticides (especially gasoline) appear to hasten 

 oxidasic activity because of their deleterious action on the reducing 

 power, when they were first applied to fresh extract, has already been 

 described. It seems very likely that the slight acceleration of the catalase- 

 action, at first, when an extract was treated with small amounts of the 

 above insecticides, may have (in part at least) much the same explana- 

 tion. That is, small amounts of gasoline, alcohol, and perhaps a few 

 others, in attacking the reductases deleteriously before they attacked 

 the catalases, removed a stronger inhibiting influence over the catalase 

 than they themselves exerted, so that a resulting initial acceleration of 

 the catalase action immediately followed. Strong treatment with the 

 insecticides, however, so greatly hindered the catalase (as well as the 

 reductase) activity, that there was a lessening of the volume of oxygen 

 liberated from hydrogen peroxide. In the case of alcohol the deleterious 

 efl'ect of strong or more prolonged treatment was quite decided. Nos. 

 18 and 20 of Table V show that while 0.5 c. c. of absolute alcohol added 

 to 2 c. c. of extract caused more oxygen to be liberated from hydrogen 

 peroxide after a period of 10 minutes treatment, 1 c. c. of alcohol in 2 

 c. c. of extract for 45 minutes before the test brought the ratio of oxygen 

 liberated by the treated to that liberated by the untreated extract down 

 to 0.089. That is, the stronger treatment not only overcame the lead 

 of the first increase, but reduced the catalase activity much below that 

 of the check. The effect of strong, prolonged treatment with gasoline 

 vapor was not so marked; it was sometimes barely able to overcome the 

 first lead or increase in catalase activity — (the lead or increase which 

 was due, as has already been suggested, to the removal of the inhibiting 

 reductases). This is illustrated by the two experiments recorded in 

 Table V, Nos. 6 and 7. In no case of strong treatment with gasoline 

 vapor was the amount of oxygen liberated brought much below that of 

 the check. 



Ammonium formate and ammonium oxalate were used in the series 

 of tests because they are known to be products formed when hydrocyanic 

 acid gas breaks down in air. Ammonium formate, in any amount tried, 

 permanently injured the catalytic action of the extract toward hydrogen 

 peroxide, as illustrated in the table (V). Ammonium oxalate, on the 

 other hand, served to slightly accelerate the liberation of oxygen from 

 hydrogen peroxide by the catalases. 



The influence of the other agents, so far as tested, are either made clear 

 in the table or may be referred to later in discussing powdered solid con- 

 tact insecticides. 



