52 THE ACTION OF THE LIVING CELL 



By means of a micro-pipette these authors injected 

 the indicator, brom thymol blue, into the eggs. Upon 

 injury of the egg by repeated thrusts of a micro- 

 needle the indicator underwent an immediate change 

 in color from blue to yellow, indicating an increase 

 in the hydrogen ion concentration. Previously 

 Chambers (1924) had noted that tearing of an egg by 

 a micro-needle leads to cytolysis which spreads from 

 the site of injury; and the experimental results of 

 Chambers and Pollack show that the increase in 

 acidity apparently precedes the cytolysis, for they 

 state that upon injury of an egg suspended in sea 

 water colored with brom thymol blue, the water ad- 

 jacent to the egg transiently became yellow prior to 

 cytolysis. 



These beautiful experiments are especially perti- 

 nent to the present discussion because they unquestion- 

 ably demonstrate the production of an acid by a single 

 cell when injured. As yet the precise mechanism 

 underlying this curious behavior is unknown. How- 

 ever, it is clear that once the acid is formed, the intra- 

 cellular proteolytic enzymes will be enabled to hydro- 

 lyze the cell proteins and hence the degradation of 

 morphological structure will ensue. Incident to this, 

 various substances of endocellular origin will be re- 

 leased into the surrounding medium — the sea water 

 in the case of the starfish egg and the body fluids in 

 the case of the cells of higher animals and plants. If 

 the foregoing is accepted, we have a rational explana- 

 tion of the mechanism by which cytost is released from 

 the injured cells. 



Various observations of the author have suggested 

 that a tissue toxin or cytost may be liberated under 



