218 R. W. GLASER. 



fats are triglycerides. This was easily accomplished by making 

 the acrolein test. Fatty tissue was dissected out of larvae and 

 crushed and the fat extracted with ether. This was filtered 

 and evaporated. An amount of the evaporated fat was then 

 heated gently with some potassium acid sulphate till vapors 

 appeared. These were smelled and the nasty odor of acrolein 

 was at once detected. Control tests were made with lard. 

 Hence, I think, I am justified in saying that insect fats are 

 like other animal fats, and further think it safe to say that since 

 insect fats are triglycerides like vertebrate fats, a fat-splitting 

 enzyme like lipase would react to the reagents used for deter- 

 mining that enzyme in vertebrate fats. It must also be con- 

 sidered that a simple ester like ethyl butyrate is chosen for the 

 test on account of the ease with which even the weakest lipase 

 will decompose it. It is therefore quite reasonable to say that 

 lipases are absent when ethyl butyrate is not acted upon. 



The tests for oxidizing enzymes were far more difficult, but 

 in the end the results were positive after the technique had been 

 perfected. 



The ordinary way of determining whether one is dealing with 

 a peroxydase or a true oxidizing ferment is by the guajacum 

 tincture method. This method, although repeated trials were 

 made, gave no results so far as the cenocytes were concerned. 

 The guajacum was never decomposed and the H2O2 seemed not 

 to be acted upon. As will be seen later, the oenocyte extract 

 really decomposed the H^, but as I had no efficient indicator, 

 it was practically impossible to tell whether there was any 

 reaction, although the amount of the reagent was decreased in 

 proportion to the amount of the extract. When large amounts 

 of extract from whole caterpillars were used, I found, as did 

 Ostwald ('07), that very often the HzO* was decomposed so 

 violently as to cause the liquid to bubble up in the test tube. 

 When using such large amounts of extract the guajacum is also 

 acted upon and the " Hartzsuspension " turns blue, showing 

 peroxydases to be present also. 



The method I applied to the cenocytes and which I am about 

 to describe, gave positive results in so far as it showed that the 

 oenocyte extract contains oxidizing ferments to a much greater 



