Article VI. — A Study of the Catalasc Content of Codling Moth 

 Larvae. By C. S. Spooner. 



At the suggestion of Professor Shelford, a series of experiments was 

 undertaken to test the hypothesis that the enzyme catalase might be a 

 determining factor in the dormant period of codling-moth larvae. The 

 method devised by Professor Burge ('1(5) was used with a few minor 

 modifications in determining the catalase content of the larvae. This 

 method consists in collecting and measuring the oxygen gas liberated 

 from neutral hydrogen-peroxide by the catalase present in the crushed 

 larvae. 



The most surprising fact discovered in these experiments was the 

 comparatively enormous quantities of oxygen obtained from the catalase 

 in a single larva — over 650 cc. being obtained in some cases. The reaction 

 w'as extremely violent, and the gas bubbled off at a surprising rate. The 

 large quantity of gas necessitated an enlargement of the apparatus, with 

 a consequent loss in accuracy. 



All tests were run for a period of twenty minutes. The quantity of 

 gas was read every minute for the first ten minutes, then at the end of 

 15 minutes, and finally at the end of 20 minutes. Although the reaction 

 had not entirely ceased at the end of twenty minutes, it had become so 

 slow as to make the continuation of readings useless. The experimental 

 error, though large, is thought to be practically constant and always in the 

 same direction ; that is, the recorded results are proportionally low for all 

 larvae. Table I gives four typical records obtained during the course 

 of these experiments. 



Table I. Typical Records of the Tolnme of Oxygen (in cc) Obtained from 

 Codling-Moth Larvae. 



413 



