136 ILLINOIS ACADEMY OF SCIENCE 



a slowly acting narcotic, such as magnesium sulphate or 

 morphia, decreased catalase verj^ slowly. 



In the plant kingdom, it is known that whatever in- 

 creases oxidation also produces an increase in catalase, 

 and whatever decreases oxidation in the plant decreases 

 catalase. This parallel relationship suggests that 

 catalase may be the enzyme in plants also principally 

 responsible for oxidation. 



CAUSE OF THE INCREASE IN THE 



RESPIRATORY METABOLISM IN 



THE FERTILIZED OVUM 



W. E. BuRGE, University of Illinois 



It is kno\^^l that by whatever method development of 

 the egg is initiated, whether naturally or artificially, 

 oxidation or respiratory metabolism is alwaj^s increased. 



The respiratory metabolism of the unfertilized egg is 

 low" while that of the fertilized egg is high. The unfer- 

 tilized egg is also poor in catalase, an enzyme possessing 

 the property of liberating oxygen from hydrogen perox- 

 ide, whereas the fertilized egg is relatively rich in this 

 enzjTue. 



We have found that whatever increases oxidation in 

 the animal produces an increase in catalase by stimu- 

 lating the alimentary glands, particularly the liver, to an 

 increased output of this enzyme, and whatever decreases 

 oxidation produces a decrease in catalase by diminishing 

 its output from the liver and by direct destruction. 



These observations suggest that the low respiratory 

 metabolism of the ovum before fertilization may be at- 

 tributed to the low catalase content of the egg, while the 

 increase in the respiratory metabolism after fertilization 

 with resulting development may be due to an increase in 

 catalase brought about by the stimulation of the egg by 

 the spermatazoon to an increased production of catalase. 



