HIBERNATION IN THE POTATO BEETLE. 40! 



same temperature conditions in the greenhouse. One lot fre- 

 quently received water, the other lot was not watered. The 

 addition of water (a drenching of the cage) had an activating 

 effect, since the beetles eventually became active and fed nor- 

 mally on the plants. In those cages not receiving water the 

 beetles were apparently unable to recover and finally perished. 

 The lack of actual contact of the animal with water evidently 

 hindered recovery. 



Dissected hibernating beetles invariably revealed accumulated 

 waste products in the rectum. In normal animals its expulsion 

 is necessary before activity and feeding is possible. It seems 

 reasonable that water actually is imbibed by the animal during 

 recovery to aid in the elimination of inert substances from the 

 digestive tract. 



CATALASE AND OXIDASE ACTIVITY. 



It seemed desirable to determine if other factors concomitant 

 with a lowered metabolic activity are involved in the hibernating 

 animal. There are many facts in the literature tending to show 

 that the power of decomposing hydrogen peroxide and the power 

 to blue guaiacum by the aid of peroxide are the specific property 

 of certain substances. Since the recognition of catalase as a 

 specific enzyme, its occurrence and distribution in various animal 

 and vegetable tissues has been investigated by a number of 

 observers. 



Certain investigators are of the opinion that the accumulation 

 of hydrogen peroxide would undoubtedly prove harmful to the 

 organism, and that the function of the catalase is to destroy the 

 hydrogen peroxide as fast as it is formed. Others hold that the 

 function of catalase may be to prevent the excessive oxidation 

 of organic substances in the living cell. Schoenbein (21), 

 however, has shown that substances which can bring about the 

 decomposition of hydrogen peroxide catalytically, can also 

 greatly increase its oxidizing power, and in proportion as a 

 substance is able to decompose the peroxide so also it can ac- 

 celerate oxidation. The power to decompose hydrogen peroxide 

 is held by Spitzer (23) to be a measure of the oxidizing power of 

 various animal tissues. Dakin (9), however, is of the opinion 



