748 TRANSACTIONS OF SECTION I. 



the diminution of the surface due to the contraction. As the latter is very small 

 the product is much below the amount of energy in the form of work done 

 actually manifested. To get over this difficulty Bernstein postulates that in 

 muscle fibres, whether smooth or striated, there are fibrils surrounded by sarco- 

 plasma, and that each fibril is formed of a number of cylinders or biaxial 

 fHipsoids singly disposed in the course of the fibril, but separated from each 

 other by clastic material and surrounded by sarcoplasma. Between the ellipsoids 

 and the sarcoplasma there is considerable surface tension, which prevents mixture 

 of the substances constituting both. The excitation through the nerve impulse 

 causes an increase of surface tension in these ellipsoids and they become more 

 spherical. In consequence the decrease in surface of all the ellipsoids constituting 

 a fibril is much greater than if the fibril were to be affected as an individual 

 unit only by an increase of surface tension, and thus the surface energy developed 

 would be correspondingly greater. The ellipsoids, Bernstein explains, are not to 

 be confused with the discs, singly and doubly refractive in striated fibre ; for these, 

 he holds, are not concerned in the generation of the contraction but with the 

 processes that make for rapidity of contraction. The extension of a muscle after 

 contraction is due to the elastic reaction of the substance between the ellipsoids in 

 the fibrils. Bernstein further holds that fibrils of this character occur in the 

 protoplasm of Amcebce, in the stalk of Vorticella, and in the ectoplasma of 

 Stentor, and this explains their contractility. ,,.„■•, * 



It may be said in criticism of Bernstein's view that his ellipcoids are from 

 their very natire non-demonstrable structures, and, therefore, must always remain 

 as postulated elements only. Further, it may be pointed out that he attributes 

 too small a part to surface tension in the lengthening of the fibre after contrac- 

 tion, and that the elasticity which muscle appears to possess is, in the last analysis, 

 but a result of its surface tension. 



As regards Quincke's explanation of protoplasmic 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 m which proto- 

 plasmic streaming occurs. Butschli's own hypothesis, however, is defective in 

 that it postulates a current in the fluid medium just outside the Amoeba and 

 backward over its surface, the existence of which Berthold denies, and Butschli 

 himself has been unable 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 

 Pelomvxa, but the current was in the opposite direction to that demanded by 

 his hypothesis. Further, his failure to demonstrate the occurrence of the postu- 

 lated' backrlow in the water about the contracting or moving mass of an Amwba 

 or a Pelomvxa, makes it difficult to accept the hypothesis he advanced to explain 

 that backilow, namely, that rupture of peripheral vesicles (Waben) of the proto- 

 plasm occurs with a consequent discharge of their contents (proteins, oils, and 

 soaps) in'o the surrounding fluid. Surface tension, further, on this hypothesis 

 would be an uncertain and wasteful factor in the life of the cell. On a prion 

 grounds also it would seem improbable that this force should be generated outside 

 instead of inside the cell. 



One common defect of all these views is that they made only a limited applica- 

 tion 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 application of surface tension as a factor in cellular life than was 

 possible ten years ago. , 



In regard to muscle fibre this is particulaily true, and microchemistry has 

 been of considerable service here. From the analyses of the inorganic con- 

 stituents of striated muscle in vertebrates made by J. Katz and others we know 

 that potassium is extraordinarily 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^he potassium salt is distributed in the fibre 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 localised in the 

 dim bands. Later and more extended observations suggested that in the dim 

 band itself, when the muscle fibre is at rest, the potassium is not uniformly 



