A letter addressed to the Earl of Rosse, President-Elect of the Royal Society / by Marshall Hall.

  • Marshall Hall
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: A letter addressed to the Earl of Rosse, President-Elect of the Royal Society / by Marshall Hall. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    supplied by these are seen to contract. This property in the spinal marrow or nerve has been designated the Vts Nervosa ; Secondly—if, as in the case of irritation of the tip of the severed tail of the triton already mentioned, any part of the cutaneous surface of a decapitated animal be irritated, certain movements are again observed. The names of Haller and of Whytt are chiefly attached to these experiments. They remained as mere sterile, unconnected, unapplied facts. No physiologist had ever imagined that the property called into action in both cases was one and the same. Far less had any physiologist pointed out any appli- cation of either to physiology—to th.e functions of life. In addition to these experimental facts, it was also known to all, that if certain surfaces of the animal body were irritated, certain movements follow : irritation of the nostril, the fauces, the larynx, induces sneezing, vomiting, coughing, respectively. Still no physiologist had imagined that the motor principle in these pathological actions had any application to physiology, or any part in any other than these very obvious “ sympathetic actions,” as they have been called. Any one of these facts might have suggested The Theory of the Spinal System ; but they never did suggest that Theory or that System. It was asserted by Haller, and all other physiologists, to Prof. Muller inclusive, that the vis nervosa only acts in one direction,—that from the point irritated towards the muscles. So long as this opinion prevailed, to identify this motor power with that in the experimental facts, and that in the sympa- thetic actions to which I have adverted, was impossible. I first detected the important Law of Reflex Action of the Vis Nervosa. From this moment the application of this motor power to explain the experimental facts, the sympathetic actions,—and a certain Class of the vital functions,—became practicable ! I consequently consider this detection of the reflex mode of action of the vis nervosa as the first and most important link in the chain of my discovery. So much for the Dynamic, or motor principle; I now come to the Anatomy of the spinal system.
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