RELATIONS OF BURSARIA TO FOOD 



33 



HRS 



The Sudan III method serves for the detection of paraffin oil 

 as well, since this stains red also. 



These experiments with oils again show that the retention or 

 extrusion depends, at least in part, upon the chemical nature 

 of the substance, and that the food vacuole functioning as an 

 organ of extrusion may vary in its response to qualitatively dif- 

 ferent chemical stimuli. 



Does the extrusion of a substance depend alone upon a response 

 to the quality of a chemical stimulus by the vacuole and what- 

 ever other part of the cell system it may be specially related to 

 in this response? If there are other factors concerned, what are 

 they? 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 17, NO. 1 



