I9I4] William N. Berg i8i 



times the weight sustained by the i mm. thick plasmodium of Chon- 

 drioderma according to Jensen's Observation, and which is quoted 

 by Macallum as an example of high surface tension in hving matter. 

 Since a thread of this smooth muscle i mm. in diameter can sustain 

 75 grams, the surface tension between it and its surrounding medium, 

 water in this case, must be over 468,000 dynes per cm. according to 

 Jensen's formula. This value becomes 234,000 dynes per cm. if 

 Jensen's formula be used as it probably was intended to be used 

 (see p. 179). The correctness of such a figure and of the method 

 used in obtaining it are to be doubted because the surface tension 

 calculated in this way is greater than that of any other known sub- 

 stance. 



The problem of the transformation of energy in striated muscle 

 is, in part at least, a problem in dynamic mechanics. It seems 

 Strange that certain investigators^^ should attempt to treat the 

 subject as if it were a problem in static mechanics. The Plas- 

 modium of Chondrioderma did not lift a gram, it did no work, for 

 the weight was only sustained, and in this respect the phenomenon 

 is comparable with the sustaining of very much greater weights by 

 smooth muscle, but is not comparable with the lifting of weights by 

 striated muscle. That the plasmodium could sustain a weight be- 

 cause of the surface tension between its surface and the surround- 

 ing medium is for the present purely an assumption, for neither 

 Jensen nor Macallum have brought f orward any evidence showing 

 that surface tension was a factor in the problem, 



THE SURFACE TENSION BETWEEN CONTRACTIL UNIT AND 



SURROUNDING MEDIUM 



To know the limiting values of the surface tension between the 

 contractu units and the surrounding medium is obviously of the 

 greatest importance in connection with the surface-tension theory. 

 Fortunately, the data in the literature on the surface tension be- 

 tween two liquids or between two Solutions are sufficiently complete 

 to point definitely to the limiting values desired. Two Solutions 

 are to be considered: (i) The Solution of biological substances 

 which constitutes the lateral surface of the contractu units and (2) 



1* Bernstein: Arch.f.d.gesammte FÄy^yio/., 1901, Ixxxv, pp. 271-312. Jensen: 

 Anatomische Hefte, 1905, xxvii, p. 842. 



