568 



Miss D. J. Lloyd. 



: 97, Sherrington, C. S., " Further Note on the Sensory Nerves of Muscles," 1 Eoy. Soc. 

 Proc.,' vol. 61 (1897). 



'97a, Sherrington, C. S., " On the Question whether any Fibres of the Mammalian Dorsal 

 (Afferent) Spinal Eoot are of Intraspinal Origin," ' Journ. Physiol.,' vol. 21 

 (1897). 



'10, Sherrington, C. S., and Tozer, F. M., " Receptors and Afferents of the Illrd, IVth, 

 and Vlth Cranial Nerves," ' Roy. Soc. Proc.,' B, vol. 82 (1910). 



'92, Tooth, H. H., " On the Relation of the Posterior Root to the Posterior Horn in the 

 Medulla and Cord," 'Journ. Physiol.,' vol. 13 (1892). 



'10, Tozer, F. M. See Sherrington and Tozer. 



'12, Tozer, F. M., " On the Presence of Ganglion Cells in the Roots of Third, Fourth, 

 and Sixth Cranial Nerves," ' Physiol. Soc. Proc.,' July 27, 1912, 1 Journ. Physiol.,' 

 vol. 45. 



The Osmotic Balance of Skeletal Muscle. 

 By Dorothy Jordan Lloyd. 



(Communicated by W. B. Hardy, F.B.S. Beceived February 24, 1915.) 



Fletcher was the first to follow continuously, for any considerable length 

 of time, the change in weight of a muscle immersed in a hypotonic solution.* 

 He found that the muscle at first increased in weight and then decreased. 

 In isotonic solution the muscle " neither gains nor loses weight." This 

 amounts to a definition of an isotonic solution. 



The changes in weight of the gastrocnemius or sartorius, the muscles 

 used by Fletcher, are slow, owing to the low value of the ratio of surface .to 

 volume. Very early in this work therefore it was decided to use a thin flat 

 muscle sheet. The sternocutaneous muscle of the frog was fixed upon. It 

 reaches its maximal intake from a hypotonic solution in from 5 to 20 minutes 

 according to the concentration of the solution and the state of the muscle. 

 In the case of so small a muscle it is possible that all the fibres are nearly 

 in the same state at the same time. This cannot be the case with larger 

 muscles. The central fibres of, for instance, the sartorius may be irritable 

 whilst the external fibres are in water rigor. Complex physical and 

 physiological reactions between the fibres must occur and complicate the 

 problem. An obvious disadvantage of a muscle with a large surface is the 

 magnitude of the error in weight due to variation in the quantity of moisture 

 adherent to the surface. The surface was always dried quickly by filter- 

 paper before weighing, and the smoothness of the curves of variation of 



* ' Journ. Physiol.,' vol. 30, p. 414 (1904). 



