CARBON DIOXIDE AS A NARCOTIC AGENT. 



461 



W 



W 

 O 

 < 





O 2O 40 60 80 100 12O 



EXPOSURE TIME MIN. 



FIG. 3. The relation between the time required for 50 per cent, cleavage 

 of Arbacia eggs and the duration of exposure to CO 2 at values from 30 

 per cent, saturation to practically complete saturation. Abscissa = minutes 

 of exposure to CO . Ordinate = minutes required for cleavage in 50 per 

 cent, of the eggs. Details are given in Table IV. 



Symbol. Experiment. 



O Circles ..................................... No. 119 



X Crosses .................................... No. 120 



A Hollow Triangles ........................... No. 121 



A Solid Triangles ............................. No. 122 



Dots ....................................... No. 128 



D Squares' .................................... No. 129 



(From lack of space, several values for exposures of over 120 minutes have 

 not been included. These values were, however, used in calculating the 

 equations the average of which 3? = 60.2 -j- i.iS.r gives the straight line 

 shown in this figure.) The slope of the curve would be unity, if recovery 

 of the eggs were instantaneous upon their removal from CO.,. 



