360 



Mr. J. B. Haycraft. Upon the Cause of [Feb. 3, 



February 3, 1881, 



THE PRESIDENT in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The Right Hon. Mountstnart Elphinstone Grant Duff, whose certi- 

 ficate had been suspended as required by the Statutes, was balloted 

 for and elected a Eellow of the Society. 



The following Papers were read : — 



I. "Upon the Cause of the Striation of Voluntary Muscular 

 Tissue.' 7 By JoHxY Berry Haycraft, M.B., B.Sc, F.R.S.E., 

 Senior Physiological Demonstrator in the University of 

 Edinburgh. Communicated by Dr. Klein, F.R.S. Re- 

 ceived December 1, 1880. 



[Plate 5.] 



The structure of striated muscular tissue has occupied the attention 

 of many histologists, and various, often antagonistic, have been the 

 views held from time to time since Schwann first investigated this 

 difficult subject. 



I bring forward with much caution and hesitation any opinions 

 of my own, nor should I venture thus far, did I not consider my 

 views susceptible of direct proof, or disproof, not being matters of 

 mere speculation, which may or may not be true, and which would 

 tend, by their introduction to the literature of the subject, to make 

 confusion worse confounded. 



In this paper an attempt will be made to account for many of the 

 observed structural phenomena of muscle on simple laws of geome- 

 trical optics, which will, if it be successful, reduce the subject to 

 comparative simplicity. I stall commence by giving a sketch of the 

 views of those physiologists who have especially written upon the 

 structure of muscle. This must not be looked upon as a complete 

 history, for I shall leave out entirely points which do not concern us 

 here. 



A Short Historical Sketch of the Views held upon the Structure of 

 Striated Muscle. — The writings of Mr. Bowman form the most im- 



