704 PHYSIOLOGY IN RELATION TO 



a justification in Professor Beale's demonstration in 1865 of the 

 ending of the muscular nerves in nucleate reticular plexuses. 

 Assuredly, the discovery of these net-works bearing nuclei does 

 away with the necessity for any further carrying on of the appa- 

 rently interminable discussions as to the existence of an 'idio- 

 muscular ' as opposed to a ' neuro-muscular ' contractility. But I 

 will take this opportunity of saying, that there are not wanting 

 purely physiological considerations, which, though not by any 

 means amounting to demonstration, do nevertheless lend some 

 little probability to the 'neuro-muscular' explanation of those 

 movements which take place in muscles separated from all con- 

 nection with central nerve-organs. Firstly, these movements are, 

 within my experience, more marked and frequent in the muscular 

 tissues of young animals ; and the history of the development of 

 nerves would lead us to expect to find a greater degree of inde- 

 pendence in the peripheral nerve-system, than we should look for 

 in the adult organism ; for nerves do not grow from cells in the 

 direction of what we know in the adult state and under low powers 

 of the microscope as their branches ; but, as Von Hensen has shown 

 (Qaain's ' Elements of Anatomy,' 7th edit. p. clxiv), two nerve-cells 

 are connected by a fibre, and it is by the withdrawal of the one cell 

 from the other, and the elongation, so to say, of the interconnecting 

 fibre, that the peripheral and central ganglionic systems respectively 

 assume their adult relations. And just so, I may add, in certain 

 annelids and lamellibranchiata, we have, as we not rarely do have 

 in the lower animals, a stereotyped though but partial adumbration 

 of what is but a single scene in the moving diorama of the develop- 

 ment of the higher; and we find the peripheral nerve-system 

 studded with eyes or other sensory organs, and possessed of a 

 prominence and importance relatively to the central nerve-ganglia 

 which is only temporarily seen in the development of more perfect 

 creatures. 



Secondly, many of the cases of death in adults, in which this 

 irritability is found to exist most commonly and markedly, are 

 cases in which, from very various reasons, the functions of the 

 intracranial nerve-centres are put into abeyance at a very early 

 stage in the process death ward. Such are (see Nysten, cited by 

 Brown-Sequard, 'Proceedings of Royal Society,' 1S62, p. an) 

 cases of decapitation, of asphyxia, and of sudden haemorrhage from 



