LIFE AND WRITINGS OF ROBERT WHYTT, M.D. 119 



to illustrate by numerous experiments. It was in this part of his inquiry that 

 he fell into controversy with Haller. This controversy led to the publication of 

 three treatises, two, namely, in a separate form, and one in the " Edinburgh Phy- 

 sical and Literary Essays." These treatises are named respectively, " An Inquiry 

 into the Causes which Promote the Circulation of the Blood in the very small 

 Vessels of Animals;" " Observations on the Sensibility and Irritability of the 

 Parts of Men and other Animals ;" " An Account of some Experiments made with 

 Opium on Living and Dying Animals." All these bear on the question at issue 

 between him and Haller, principally as to the dependence or non-dependence 

 of irritability, now called contractility, in muscular fibre, on the presence of 

 nerves. It was already remarked, that recent physiology for the most part 

 rejects Whytt's view, in so far as it attributes to nerves the vital properties of 

 the solids concerned in such vegetative acts, while it fully admits the influence 

 exercised by the nervous system over their course and order. If this distinction be 

 borne in mind, the precise bearing of the following passage from one of our most 

 recent and most distinguished cultivators of the physiology of the nervous system 

 on Whytt's doctrine, will be fully understood : — " Before treating," says Mr 

 Brown-Sequard " of the reflex changes in nutrition, which are by far more fre- 

 quent and more important to be well investigated than the reflex secretions, I 

 must remark that the reflex character of facts more or less similar to those I 

 have to mention has been known for a long while ; and that the modern theory 

 is not far in advance of that given in this respect by Robert Whytt in the last 

 century. In one of his important works he has shown that the normal and 

 morbid sympathies either for movements, nutrition, or secretion, are reflex phe- 

 nomena. Still more, he has shown that the share of blood-vessels is very great 

 in many of these phenomena." * In all such cases, however, it is not to be 

 admitted that the actual properties of the molecules concerned are determined 

 by nerves, but only the course and order of molecular action. 



It will be enough to show, in a few words, the nature of Whytt's controversy 

 with Haller as to the contractility of the muscular fibre. What he insisted on, 

 in opposition to Haller, is, that the contractility of muscular fibre depends on 

 an influence derived from the nerves, — that is to say, he gave to the nervous 

 power the double ofiice of imparting to muscular fibre the susceptibility of con- 

 tracting on the condition of the application of a stimulus, and, as a stimulus, of 

 exciting this susceptibility into actual contraction. The influence conveyed by a 

 nerve to a muscular fibre is manifestly one of the causes by which its contraction 

 is excited. But it does not at all follow that a similar influence conveyed by the 

 nerve should impart to the muscular fibre its susceptibility of contracting. A 

 muscular fibre contracts under the application of other kinds of stimulation, 



* Lectures, « Lancet," 1858, vol. ii. p. 468. 



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