1914] William N. Berg 195 



To summarize : The conditions existing in a living muscle are 

 not such as to give rize to any very great surface tension between 

 two adjacent regions. A surface tension of about 62 dynes between 

 contractu sohition and adjacent lymph is obtained by assuming that 

 at the beginning of the contraction phase, the contractu unit is 

 bathed by a saturated aqueous Solution of an inorganic salt, having 

 a maximum surface tension of 85 dynes, and immediately in contact 

 with this is the adjacent lymph, consisting of a dilute aqueous Solu- 

 tion of an organic substance having a minimal surface tension of 

 about 23 dynes/cm. But, as pointed out before, there is no par- 

 ticular reason for assuming that these values exist coincidently, or 

 that they exist at all in muscle. The maximum value at the begin- 

 ning of the contraction is there fore, theoretically, not far from 62 

 dynes per cm. This may be entirely sufficient to account for the 

 movement of salts, secretions, etc., but it is entirely insufficient to 

 account for the lifting power of muscle, as indicated by our calcula- 

 tions already publisht^' and recently corrected (see p. 179). 



Washington, D. C. 



17 Berg : Biochemical Bulletin, 1912, ii, p. 109. 



