‖ medulla Biol.
(mɪˈdʌlə)
[L. medulla pith, marrow, prob. cogn. w. medius middle.]
1. Anat. The marrow of bones; also, the spinal marrow. Also, † the substance of the brain.
| 1651 Raleigh's Ghost 87 The inward medulla or marrow of the brain. 1668 Phil. Trans. III. 889 He affirms, that the whole Substance called the Medulla of the Brain and the After-brain is a Heap of Fibres or Vessels. 1813 J. Thomson Lect. Inflam. 393 The inner surface of the new bone..is lined with a membrane containing medulla. 1845 Todd & Bowman Phys. Anat. I. 103 The cancelli are filled with fat, or medulla, the marrow of bone. 1854 Jones & Siev. Pathol. Anat. (1875) 147 These tumours always arise either from the inner layer of the periosteum or from the medulla of bone. 1873–5 Nicholson Zool. Glossary, Medulla. Applied to the marrow of bones; or to the spinal cord, with or without the adjective ‘spinalis’. |
| attrib. 1904 Brit. Med. Jrnl. 17 Sept. 649, I put her on red medulla tabloids. |
b. (More fully
medulla oblongata:
lit. ‘prolonged marrow’.) The hindmost segment of the brain, or continuation of the spinal cord within the cranium.
| 1676 Glanvill Ess. iii. 5 Those Nerves, which..are found by late Anatomists to proceed from the Medulla Oblongata. 1722 Quincy Lex. Physico-Med. (ed. 2) 51 The third [process] goes backwards on the upper side of the Medulla. 1878 Bartley tr. Topinard's Anthrop. 103 Section of the spinal cord where it joins the medulla oblongata. 1899 Allbutt's Syst. Med. VII. 222 A softening patch on the left side of the medulla. |
c. The central parts of certain organs (
esp. the kidney) as distinguished from the cortex.
| 1878 J. S. Bristowe Theory & Pract. Med. 841 The vessels—and more especially those of the medulla, the Malpigian tufts, and the stellate veins on the surface [of the kidney]—become more or less deeply congested. |
d. The soft fatty substance (the ‘white substance’ of Schwann) which forms the sheath of a nerve.
| 1839–47 Todd Cycl. Anat. III. 592/2 The real structure of the primitive nerve fibre appears to be a tube composed of homogeneous membrane, containing a delicate, soft, pulpy, semi-fluid, and transparent medulla. 1873 A. Flint Physiol. Man, Nerv. Syst. i. 19 These [nerve] fibres..contain, enclosed in a tubular sheath, a soft substance called the medulla. |
e. The nerve cord in certain worms.
| 1878 Bell tr. Gegenbaur's Comp. Anat. 167 A median one [sinus]..embraces in Clepsine and Piscicola, the alimentary canal and the ventral medulla. |
f. The ‘pith’ of mammalian hair. Also, the soft fibrous substance which occupies the axis of the capsule of a growing feather.
| 1826 Prichard Researches Phys. Hist. Man. (ed. 2) I. 136 The pith or medulla [of hair] appears to be endowed with a species of vitality. 1835–6 Owen in Todd's Cycl. Anat. I. 353/1 When the quill of the feather has acquired due consistence, the internal medulla becomes dried up. 1842 Prichard Nat. Hist. Man. (ed. 2) 95 Weber declares the human hair to consist of a homogeneous substance, in which no distinction of cortex and medulla can be perceived. |
g. The endosarc of protozoa.
| 1888 Rolleston & Jackson Anim. Life 833 The protoplasm is either similar throughout, or it is divisible into an exoplasm (cortex) and endoplasm (medulla). |
2. Bot. The pith or soft internal tissue of plants.
| 1651 Raleigh's Ghost 96 In the Medulla or marrow of the Plant there is a genital power or vertue. 1760–72 tr. Juan & Ulloa's Voy. (ed. 3) I. 286 The pod [of the guava], opened longitudinally, is found divided into several cells, each containing a certain spungy medulla. 1880 Gray Struct. Bot. iii. §3. 75 The Pith or Medulla, consisting entirely of soft..thin-walled cells. |
b. = medullin.
| 1819 J. G. Children Chem. Anal. 298 Medulla was obtained by Dr. John, from the pith of the sunflower. |
† 3. fig. The ‘pith’ or ‘marrow’ of a subject. Often in
mod.L. titles of books (
cf. marrow n.1 1 d); hence used for: A compendium, abridgement, summary.
Obs.| 1643 Milton Divorce Introd., Wks. 1851 IV. 12 Their youth run ahead into the easy creek of a System or a Medulla, sails there at will. 1660 South 36 Serm. (1720) II. 17 Their preaching Tools, their Medulla's Notebooks, their Mellificiums, Concordances, and all. 1704 Swift T. Tub v. Wks. 1755 I. 97 An infinite Number of Abstracts, Summaries, Compendiums,..Medullas..and the like. 1769 Bush Hibernia Cur. To Rdr. 12 The abridgers, who..engage to furnish you, at a very easy expence, with the medullam of your civil history. |