W. J. CROZIER 



725 



From a number of tests of this kind, data were secured for the 

 construction of Fig. 2. It is apparent that even moderate tension 

 exerts a very decided effect upon the penetrability of this tissue for 

 0.01 N dichloroacetic acid. A similar result was had with other 

 weak acids; the coagulative action of the stronger acids tends to 

 obscure the phenomenon. 



e 



g 



•T-« 



03 



Gm. 



10 



20 30 



Tension 



40 



50 



I'lG. 2. Penetration of tissues under tension, by 0.01 N dichloroacetic acid; 

 25°C. Ordinate, penetration time, minutt's; abscissa, tension, gm. 



Since pieces of mantle tissue subjected for 10 minutes to tensions 

 of 30 to 40 gm., in sea water, quickly regained about their normal 

 penetrability when the traction was removed, the effect of tension is 

 (within limits) reversible. 



The effect of tension noted in these experiments cannot be as- 

 cribed to manipuhitinii (^f the tissue during its preparation. Undue 



