Observations on the structure and functions of the spinal cord / by R.D. Grainger.

Date:
1837
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the structure and functions of the spinal cord / by R.D. Grainger. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    168/176 (page 152)
    flying, &c. It appears, however, that the cord is itself efficient to produce the motions of progression, although, doubtless, all power of controlling, directing, quick- ening, retarding or stopping these actions is a purely cerebral function. Instinctive motion.*— This term is usually applied to such actions as the sucking performed by young infants, deglutition, breathing, &c. Dr. Hall has so very satisfac- torily elucidated these phenomena, and they have been so minutely considered in the former part of this treatise, that it is unnecessary to dwell on them in this place. Involuntary Motions. The real character of the con- traction of the heart, intestine, secreting canals, &c. is, as yet, unknown. The heart’s action is very commonly sup- posed to result from the immediate contact of the blood, with its muscular substance; a similar account is also given of the peristaltic motion; whilst as far as the flow of saliva into the mouth, of the gastric juice into the stomach, and the bile into the intestine, it is vaguely attributed to what is called, continuous sympathy. This question is intimately associated with that relative to the endowments of the great sympathetic. The theory by which the contraction of the involuntary muscles is referred to immediate contact with their fibres, is, when carefully considered, very unsatisfactory. It may, in the first place, be observed, that in no organ does actual contact take place ; there is always a membrane interposed between the fleshy fibres and the contents of the organ. But, even allowing that where the muscular planes, as in the intestine, are so thin as to allow the food to approach * It is necessary to distinguish between instinctive motions, such as those mentioned in the text, and the instinctive principle which impels animals perform certain acts, such ns the construction of nests by birds ; the form are spinal, the latter, I believe, cerebral phenomena.