September 21, 1917] 



SCIENCE 



295 



THE CATALASE CONTENT OF LUMINOUS AND 

 NON-LUMINOUS INSECTS COMPARED" 



According to Dubois- and others the 

 production of light by luminous organisms is 

 an oxidative process. If this is true then 

 it would seem that oxidation should be cor- 

 respondingly more intense in luminous insects 

 than in non-luminous insects. It has been 

 shown that the catalase content of the dif- 

 ferent muscles of animals is proportional to 

 the amount of oxidation in these muscles and 

 that the catalase is increased or decreased 

 under the same conditions under which ox- 

 idation is increased or decreased.^ This and 

 similar evidence would seem to indicate a 

 close relationship between the catalase content 

 of a tissue and the amount of oxidation in 

 that tissue If oxidation is more intense in lu- 

 minous than in non-luminous insects then 

 the catalase content per unit of weight of 

 luminous insects should be greater than that 

 of non-luminous insects. The object of this 

 investigation was to determine if the catalase 

 content per unit of weight is greater in a lu- 

 minous insect, such as the firefly (Photinus), 

 than it is in non-luminous insects, such as 

 moths, butterflies, honey-bees and bumble- 

 bees. 



Method. — After the insect was weighed it 

 was ground up with sand in a mortar. This 

 ground material was added to 50 c.c. of hy- 

 drogen peroxide in a bottle'arid as the oxygen 

 gas was liberated from the hydrogen peroxide 

 by the catalase it was conducted through a 

 rubber tube into an inverted burette previously 

 filled with water. In this way the amount of 

 oxygen liberated in ten minutes from 50 c.c. 

 of hydrogen peroxide was collected. The vol- 

 vme of oxygen was read off directly from the 

 burette, where it had displaced the water. 

 After this volume had been reduced to stand- 

 ard atmospheric pressure the resulting volume 



1 From the Physiological Laboratory of the Uni- 

 versity of Illinois. From experiments carried out 

 at Nela Research Laboratory. 



- Dubois, ' ' M&anisme intime de la production 

 de la lumi&re ehez les organismes vivants, " Soc. 

 Linneeiine dc Lyon, Imprimcrie A. Eey. 



3 Burge, The American Journal of Physiology, 

 Vol. XLL, No. 2, August, 1916. 



was taken as a measure of the catalase content 

 of the insect. Knowing the weight of the 

 insect, the amount of catalase per 30 milli- 

 grammes of material was calculated. The 

 calculation was made on the basis of 30 

 milligrammes of material, because it was 

 found that three of the fireflies used weighed 

 approximately 30 milligrammes. The hy- 

 drogen peroxide was prepared by diluting 

 commercial hydrogen peroxide with an equal 

 volume of distilled water. A full description 

 of the method may be found in a previous 

 publication. 



Experiments. — T h r e e fireflies previously 

 ground up in a mortar with sand were intro- 

 duced into a bottle containing 50 c.c. of hydro- 

 gen peroxide and the amount of oxygen liber- 

 ated in 10 minutes was determined. Ten such 

 determinations were made with an average 

 of 118 c.c. of oxygen per 30 milligrammes 

 of firefly. Similarly a moth ground up in 

 sand was introduced into 50 c.c. of hydro- 

 gen peroxide and the amount of oxygen liber- 

 ated determinedj The average amount of 

 oxygen liberated by moths was 8 c.c. of oxygen 

 per 30 milligrammes of material. Determin- 

 ations were also made using honey-bees, bum- 

 ble-bees, and butterflies. The amount of oxy- 

 gen liberated in none of these determinations 

 exceeded 25 c.c. of oxygen per 30 milligrams 

 of material. , 



Conclusions. — The catalase content of a lu- 

 minous insect where oxidation is presumably 

 more intense is greater than that of a non- 

 luminous insect where oxidation is less 

 intense. 



W. E. Burge 



TJniversitt of Illinois 



effect of smelter gases on insects' 

 It is often claimed that the waste gases, 

 particularly sulphur dioxide, thrown off dur- 

 ing the process of smelting copper, lead and 

 some other ores, have a very decided influence 

 on the number of insects in the vicinity of 

 the smelters. Some believe that few if any 



1 Contribution from the laboratories of the 

 American Smelting and Refining Co., department 

 of agricultural investigations. 



