LIFE AND WRITINGS OF ROBERT WHYTT, M.D. 123 



vital and other involuntary motions. In respect, indeed, to one great order of 

 sympathies, it is a simple extension of that work. 



He rejects the opinion that sympathies depend on the continuity of the 

 cellular tissue throughout the body, on the peculiar distribution of the blood- 

 vessels, on the affinities of particular membranes, or on identity of organic 

 structure in remote parts. He refers to Willis, as the author of the doctrine 

 that all sympathies are effected through nerves, while he rejects his parti- 

 cular view of all sympathies being dependent on the varied communications 

 of different nerves throughout the body. He maintains that all sympathies 

 take place through the nervous centre by means of nerves ; for example, 

 that the tickling of the fauces excites vomiting, not because there is a commu- 

 nication between the nerves of the fauces and the nerves of the stomach, but 

 because the nerves of the part affected by the tickling convey the impression 

 to the nervous centre, whence, by the constitution of the living frame, a motor 

 influence is transmitted through nerves to the many muscular fibres, by the simul- 

 taneous action of which vomiting is effected ; again, for a second example, an 

 ulcer of the bladder is attended with a pain in the sole of the foot, not because 

 the nerves of these two parts communicate in their course, but because the im- 

 pression made on the nerves by the irritation of the bladder being carried on- 

 wards to the nervous centre, excites an influence by which the nervous fibrils 

 spreading to the sole of the foot are stimulated, so that these two sets of nervous 

 fibrils become similarly affected. 



" If it should be objected," he says, " that it is as difficult to account for a 

 sympathy between the nerves, at their origin in the brain, as in their course to the 

 several parts, where they happen to be connected ; I answer, that the purpose of 

 these observations is not to explain how the different parts of the body can be 

 endowed, by means of the nerves, either with a sentient or a sympathetic power, 

 but to endeavour to trace the sympathy of the nerves to its true source, which I 

 take to be the brain and spinal marrow." 



Sympathies are commonly referred to the two heads of sympathetic acts and 

 sympathetic sensations, while, under the former head, it should be understood, are 

 included not only such acts as vomiting from tickling the fauces, but also acts 

 belonging to the circulation of the blood, secretion, and the vegetative functions 

 in general. Among the examples given by Whytt falling under what may be 

 called the first order of sympathetic acts, is sneezing from a sudden light falling 

 upon the eye, yawning, and even vomiting, from the sight of a person yawning 

 or vomiting, closing of the eyelids from a loud sound, such as the report of cannon, 

 convulsive movements of the whole body from tickling the soles of the feet. As 

 examples of sympathetic motions of the second order, many are the results of 

 affections of the mind, such as redness and glow of the face from sense of shame, 

 paleness of the face from fear, flow of the tears from grief, abundance of limpid 



VOL. XXIII. PART I. 2 L 



