Further researches on the grey substance of the spinal cord / by J. Lockhart Clarke.

  • Jacob Augustus Lockhart Clarke
Date:
1859
Catalogue details

Licence: Public Domain Mark

Credit: Further researches on the grey substance of the spinal cord / by J. Lockhart Clarke. 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.

    3/48 page 437
    XXII. Further Researches on the Grey Substance of the Sjnnal Cord. By J. Lockhakt Claexe, Esy., F.R.S. Eeceived Jime 17,—Eead June 17, 1858. Since the appearance of my second series of investigations on the structure of tlic Spinal Cord, certain modifications in the method I employ have enabled me to carry my inquiries to a still greater extent, and in many respects beyond the limits of what was actually known on this important subject. By this modified metliod the elementary nerve-tissues undergo less alteration from their natural state; for the most minute nerve- cells and their processes, as well as the finest fibres, are permanently preseixed, and display a sharpness of outline unattainable by any other mode of preparation employed at the present day; while sections the one-twelfth of an inch in thickness may he rendered perfectly transparent*. Many of the older anatomists, from Baetholinus downwards, had obseixed that the grey substance of the spinal cord is softer, more delicate and more vascular than the surrounding white columns; but Eolando was the first to point out a diversity in its structure. He observed, chiefly in quadrupeds, that on each side the posterior third of the grey crescent consists of a peculiar cineritious substance, which presents a different aspect from that which forms its two anterior thirds: it is different in colour, darker, and less redf. Eolando, however, assigned too large a space to this “new substance,” which does not comprise so much as the posterior third of the grey crescent, but forms only a comparatively narrow and curved lamina or band around the extremity of each cornu, and, when Hewed in a thin section by transmitted light, is found to be actually much paler and more transparent than the rest of the grey crescent. That this lamina is the part indicated by Eolando appears evident on examining his plates J. Now I propose, also, to make a primary but different division of each posterior cornu * See Appendix. t “ Non e molto difficile il vedere iiel midollo spiuale di bue, di maiale e di pecora, che le coma posteriori della sostanza ciuericcia, che in quest! si mostraiio molto pin spesse e pin grosse che nell’ uomo, sono formate in gran parte da mia sostanza ciuericcia particolare, che presenta un aspetto diverse da quello, che si osser^ a nella porzione che forma i due terzi anterior! della mezza Inna. Questa nuova sostanza e pin gelatinosa, cio die fa si che prende eziandio un colore diverse, e che in generale e meno rossigno, e di uu colore piii oscuro.” Bice/'cJie Anatomiclie sulIa Strvffura del Midollo Spinale (con figure), 1821, Torino, p. 60. He states that it was only in quadrupeds that he succeeded in distinctly seeing this new substance, partly because in them the spinal cord may be obtained in that state of freshness which is more favourable for observation, and partly because tliis substance is found there in greater abundance ; but that, nevertheless, in Man, imequivocal traces of it may be seen in the lumbar region. J Some authors, however,- seem to thtnk that the gelatinous suhstance comprises a larger portion of each MDCCCLIX. ^ 3 M
    digitised image 1
    digitised image 2
    digitised image 3