494 



SCIENCE 



[N. S. Vol. XXXII. No. 824 



toplasmic movement and streaming, as well 

 as of muscular contraction, Biitschli has 

 shown that it is based on a mistaken view 

 of the structure of the cell in Chara and 

 other plant forms in which protoplasmic 

 streaming occurs. Biitschli 's own hypoth- 

 esis, however, is defective in that it postu- 

 lates a current in the fluid medium just 

 outside the Amoeba and backward over its 

 surface, the existence of which Berthold 

 denies, and Biitschli himself has been un- 

 able to demonstrate, even with the aid of 

 fine carmine powder in the fluid. He did, 

 indeed, observe a streaming in the water 

 about a creeping Pelomyxa, but the current 

 was in the opposite direction to that de- 

 manded by his hypothesis. Further, his 

 failure to demonstrate the occurrence of 

 the postulated back-flow in the water about 

 the contracting or moving mass of an 

 Amceba or a Pelomyxa, makes it difficult 

 to accept the hypothesis he advanced to 

 explain that back-flow, namely, that rup- 

 ture of peripheral vesicles {Waheti) of the 

 protoplasm occurs with a consequent dis- 

 charge of their contents (proteins, oils and 

 soaps) into the surrounding fluid. Surface 

 tension, further, on this hypothesis would 

 be an uncertain and wasteful factor in the 

 life of the cell. On a priori grounds also 

 it would seem improbable that this force 

 should be generated outside instead of in- 

 side the cell. 



One common defect of all these views is 

 that they made only a limited application 

 of the principle of surface tension. This 

 was because some of its phenomena were 

 unknown and especially those illustrating 

 the Gibbs-Thomson principle. With its aid 

 and with the knowledge of the distribution 

 of inorganic constituents in animal and 

 vegetable cells that microchemistry gives 

 us we can make a more extended applica- 

 tion of surface tension as a factor in cellu- 

 lar life than was possible ten years ago. 



In regard to muscle fiber this is particu- 

 larly true, and microchemistry has been of 

 considerable service here. From the an- 

 alyses of the inorganic constituents of stri- 

 ated muscle in vertebrates made by J. Katz 

 and others we know that potassium is ex- 

 traordinarily abundant therein, ranging 

 from three and a half in the dog to more 

 than fourteen times in the pike the amount 

 of sodium present. How the potassium salt 

 is distributed in the fiber was unknown 

 before 1904, in which year, by the use of a 

 method, which I had discovered, of demon- 

 strating the potassium microchemically, the 

 element was found localized in the dim 

 bands. Later and more extended observa- 

 tions suggested that in the dim band itself, 

 when the muscle fiber is at rest, the potas- 

 sium is not uniformly distributed, and it 

 was found to be the case in the wing mus- 

 cles of certain of the insecta — as, for ex- 

 ample, the scavenger beetles — in which the 

 bands are broad and conspicuous enough to 

 permit ready observation on this score. In 

 these the potassium salt was found to be 

 localized in the zones of each dim band ad- 

 jacent to each light band. Subsequently 

 Miss M. L. Menten, working in my labora- 

 tory and using the same microchemical 

 method, found the potassium similarly lim- 

 ited in its distribution in the muscle fibers 

 of a number of other insects. She deter- 

 mined, also, that the chlorides and phos- 

 phates have a like distribution in these 

 structures, and it is consequently probable 

 that sodium, calcium and magnesium have 

 the same localization. 



Macdonald has also made investigations 

 on the distribution of potassium in the ■ 

 muscle fiber of the frog, crab and lobster, 

 using for this purpose the hexanitrite re- 

 agent. He holds, as a result of his obser- 

 vations, that the element in the uncon- 

 tracted fibril is limited to the sarcoplasm 

 in the immediate neighborhood of the 



