Physiology of secretion.

  • Mathews, Albert P.
Date:
1898
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Licence: Public Domain Mark

Credit: Physiology of secretion. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    exerted a secretory effect upon the gland, he considered the secretion to be due to Jacobson's nerve alone. He concluded, therefore, that stimulation of the sympathetic enormously in- creased the content of organic solids in the cerebral saliva. The sympathetic must hence act on the gland cells so as to render their contents far more soluble. From Langley's results, how- ever, we can safely conclude that the saliva, secreted when both nerves are stimulated, is not pure cerebral saliva, but largely, if not wholly, augmented sympathetic saliva. Like all sympa- thetic saliva, it is more concentrated than the saliva secreted under the influence of the dilator nerve, because it is expelled without dilution. f. Other Evidence of the Muscular Nature of the Mechanism of Sympathetic Secretion. Very clear evidence, also, has been brought forward by Eck- hard,^^ von Wittich'' and Heidenhain^^ himself that the sympa- thetic causes at least the major part of its secretion, by a com- pression of the ducts and alveoli. The parotid gland of the sheep is an albuminous gland, capable of secreting against a pressure of 400-500 m. m. of water (Eckhard). If while secret- ing against a somewhat lower pressure (200—300 mm.) the cervical sympathetic be stimulated, the water rises suddenly in the manometer for some distance (30-100 mm.). On ceasing stimulation the secretion riislies hack at once into the gland nearly, tho?igh never quite, to its former level. The higher the pressure the more sudden the flow backward. The quick rise at the beginning of stimulation and the abrupt back flow of the secretion at the end plainly suggest that the nerve caused compression of the ducts and alveoli, and thus pressed out the secretion. On ceasing stimulation these structures dilated, and the secre- tion, being under pressure, rushed back into the gland. I see no other explanation for the back flow, as it takes place too suddenly and at too low a pressure (200 mm. water) to be due to back filtration. Heidenhain's observation is less striking, but it is similar to