Causation of Vital Movement. 



433 



respiration and carries on a chemical exchange, all of which are 

 indispensable for contractility, i.e., for its work, and since secretion 

 generalised signifies merely the throwing off of broken-down products, 

 it is wanting only in automatism, that faculty of reacting to certain 

 stimuli, which remained reserved for protoplasm. In this there is 

 nothing opposed to the assumption that protoplasm as opposed to 

 muscle possesses elementary nervous properties. 



The above is sufficient to show the transition to the very highly 

 developed motor apparatus, which distinguishes the animal kingdom 

 from almost its lowest stages — I mean the bi-cellular apparatus, which 

 consists of separate cells united only for one purpose, one of which 

 presents the exciting nerve, the other the obedient muscle. 



From past experience we know that division of the nerve, or more 

 correctly speaking, removal of the nervous cell substance, condemns 

 the muscle to rest. The stimuli then start from the nerve-cell, to 

 them the muscles react by doing work, and they are conveyed to the 

 muscles through the continuation of the cell which the nerve-^frre 

 presents. We need not yet trouble ourselves how the excitation of 

 the nerve-cell arises, whether through external — sensory — stimuli, or 

 through an enigmatical psychic act, or through chemical influences ; 

 certain it is that these were before the division of the nerve the sole 

 impulse to the muscle's movements. But what the muscles lack we 

 can supply artificially, and more ; we can put the nerve-remnant in 

 such manifold states of excitement as it never before experienced from 

 its cell-body, so that the muscle is compelled to undergo many kinds 

 of movement quite new to it, and we can attain the same result by 

 direct stimulation of the muscle. 



In the circle of these experiences arose the controversy, not yet 

 quite ended (9), as to muscular irritability, properly the question 

 whether it was, in general, possible to stimulate anything artificially 

 that is not nerve, that is, to set free the activity peculiar to a non- 

 nervous structure by the means at our command. 



Haller, who was the first to occupy himself minutely with the 

 stimulation of muscle, and introduced the term irritability, decided, 

 but only incidentally and by the way, that the stimulus could strike 

 also the ramifications of the nerve in the muscle, and he was far from 

 interesting himself in the question in the modern sense, or from 

 suspecting the point of view from which the independent irritability 

 of muscle would later on be questioned. We ought not to blame him 

 much for the latter, since even to-day it is not easy to understand the 

 motives of an opposition now continued for more than a century. At 

 the outset, if I am not mistaken, the teaching of the Animistic, or as 

 it might now be called, the Neuristic school, led to the conception 

 that not only the excitation and regulation of the various functions, 

 but the actual endowment of the several tissues with their respective 



