THE DOCTRINE OF HUMAN AUTOMATISM. 263 



animals, after it has been taken out of the body, is a clear proof of 

 their purely automatic nature; and there is no reason to regard the 

 prehensile actions of the Iiydra, or other animals of similar grade 

 of organization, in any other light. 



But with the development of a special muscular apparatus, 

 and the limitation (with accompanying exaltation) of the sensory 

 endowments of particular parts of the organism, we find a nervous 

 mechanism interposed, the primary office of which is obviously 

 " internuncial " merely. Thus, in the humble ascidian, rooted 

 to one spot during all but its free embryonic stage of existence, 

 and obtaining both its food and the oxygen required for the 

 aeration of its blood by currents sustained by the vibration of 

 the cilia that line its alimentary canal and respiratory sac, an 

 action that resembles coughing is the only sign it gives of any 

 but a purely vegetative existence. The orifice of the dilated 

 pharynx which forms the respiratory sac is fringed with short 

 tentacles, from which nerve-fibres proceed to a ganglionic centre 

 in their neighbourhood ; and from this centre we find motor fibres 

 ramifying over the muscular mantle in which the body is inclosed. 

 And thus if the ciliary current should draw inwards a particle of 

 unsuitable size or character, the contact of this with the guardian- 

 tentacles excites a rellex contraction of the muscular sac, whereby 

 a jet of water is squirted out that carries the offending particle 

 to a distance. It is obvious that this act no more represents 

 conscious intention on the part of the ascidian, than the cough 

 of the infant represents a desire to get rid of an uneasy sensa- 

 tion in its throat ; in the one case as in the other, the adaptive- 

 ness of the action to the purpose it answers is simply that of 

 a piece of mechanism ; and we characterize it, therefore, as 

 automatic. 



It has been shown by Professor Huxley that Descartes, who 

 distinctly recognized the purely mechanical nature of such actions, 

 had made as near an approach as he could do to what we now 

 regard as their true rationale, in attributing them to a reflexion of 

 the " animal spirits " in the nerve-centres from the sensory to the 

 motor nerves ; and he seems further to have been in advance of 

 his successors in maintaining that the impressions which call forth 

 reflex movements may do so without being consciously felt. It 



