230 Dr. Beale Croonian Lecture. [May 11, 



be delivered annually to the Fellows of the Royal Society. It appears 

 that the subject of muscular motion was selected by many of the earlier 

 Croonian lecturers, and it has been generally considered that the Croonian 

 Lecture should be confined to this department of local motion. Although 

 this view was founded upon a misconception, it would indeed have been 

 difficult to have selected a subject better adapted for frequent and repeated 

 investigation and illustration than muscular motion. Notwithstanding 

 more than a century has elapsed since the first Croonian Lecture was de- 

 livered, the nature of muscular motion, and the mechanism taking part in 

 its production, still remain to be discovered. In this as in every other de- 

 partment of natural knowledge, it is to be noticed that the gradual pro- 

 gress made by the unremitting labour of successive observers, so far from 

 exhausting the fields of scientific inquiry, seems but to prepare the way for 

 ever-increasing advance. 



By the excellent custom of appointing lecturers to deliver at certain 

 intervals of time lectures upon the same department of natural knowledge, 

 the actual progress achieved from time to time may be distinctly defined 

 and duly registered, and new lines of inquiry suggested for future investi- 

 gators in the same department. Although I have been led to choose for 

 the subject of my lecture an anatomical question which seems extremely 

 simple and of limited extent, I am compelled to leave many points but 

 imperfectly studied ; and notwithstanding I have worked at this question 

 earnestly for several years, my conclusions are in many respects still 

 incomplete. 



It is remarkable how the positive determination of a simple question of 

 fact may, as it were, recede as the investigation advances. However minute 

 the detail, more and ever more detail seems required before all doubt can 

 be removed from the mind of the student. 



I should not have ventured to ask the attention of the Fellows of the 

 Royal Society to minute and, necessarily, in many respects incomplete 

 anatomical detail, were it not that some broad questions of very general 

 interest are involved in the inquiry I have undertaken ; and I think that I 

 shall render what I have to say far less tedious and irksome than it would 

 otherwise be, if I state, in the first instance, the questions proposed for dis- 

 cussion, and the general nature of the inferences I have arrived at. 



It seems to me that we can scarcely hope to determine the manner in 

 which the nervous system influences the muscular and other tissues, until 

 we have ascertained how the ultimate branches of nerve-fibres are arranged, 

 and have demonstrated by actual observation, or proved by other means, 

 whether the nerves are disposed so as to form loops or plexuses, or whether 

 they exhibit distinct ends, or terminate in special organs or by becoming 

 continuous with other tissues. And it is impossible to separate from this 

 inquiry the further and wider question, concerning the necessary structure 

 and typical arrangement of a nervous apparatus. 



