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



is hardly less of an assumption than his sentient principle. How little he was 

 dogmatic on this point, is proved by the following paragraph:—" If any one 

 should yet contend that the sentient principle governing the vital motions is yet 

 different from the rational soul, I shall not further dispute the matter with him ; 

 since whatever is advanced in the present essay upon the subject of the involun- 

 tary motions of animals, will hold equally true, whether the sentient and rational 

 soul be supposed distinct or otherwise."* 



Though Whytt made no pretension to advance the knowledge of his day as to 

 the mere anatomy of the nervous system, the merit may be claimed for him of 

 having first published a view which was then only a probable assumption, but 

 which is now regarded as fully established. The point referred to constitutes one 

 of the most prominent features in the recent descriptions of that system, namely, 

 the complete isolation of the minute filaments entering into the nerves ; in other 

 words, the belief that their component filaments are unbranched, and quite dis- 

 tinct one from the other, from their origin to their termination. Though some 

 confusion of ideas exists on this subject, which after Whytt's time was never 

 forgotten, it will be easy to bring proofs, as will be seen hereafter, that he was 

 the chief authority thereon for the long period of seventy years. 



But it is impossible not to perceive that the belief in the complete isolation of 

 the filaments of the nerves must have been the direct step to the idea, whether 

 that idea shall or shall not require after modification, of the white fibres of the 

 nerves and medullary substance being merely conductors of influences generated 

 elsewhere, and therefore to the correlative notion of the grey matter being the 

 seat of force. Discovery still proceeded in the path indicated by Whytt, when 

 the nervous system in animals low in the scale of being was shown to consist of 

 a detached series of nervous knots connected by commissures, and communicat- 

 ing with the external surfaces by nervous filaments. And even when animals 

 were remarked destitute, like vegetables, of nerves, but still performing move- 

 ments analogous to those determined through nerves, so as to render it necessary 

 to omit all reference to nerves, by saying that one animal surface receives im- 

 pressions and another originates movements, there is still merely an extension 

 of Whytt's proposition, however unwilling he might have been, if still in the 

 world, to bow to its truth. What is here claimed for Whytt, is merely the initi- 

 ation of one or two principal steps in the way to this generalisation, without in 

 the least derogating from the unquestionable merit of the subsequent labours, 

 particularly of Unzer, Prochaska, and Marshall Hall. 



Hesides these more general observations, a few words in detail may be added 

 for the full understanding of the views which Whytt adopts. He does not 

 attempt to systematise the animal movements beyond the common division into 



* Works, p. 150. 

 VOL. XXIII. PART I. 2 H 



