480 



GLAND. 



that the nature of the sex may in some degree 

 be modified by circumstances affecting the 

 female at an early period of utero-gestation. 

 In reference to this subject we ought not to 

 omit the mention of a fact which is well esta- 

 blished, viz. that when the cow bears two calves, 

 one of which is a male, the other, exteriorly re- 

 sembling the female, has its reproductive organs 

 internally imperfectly formed, being of that 

 kind of hermaphrodite formation usually called 

 the Free Martin.* 



BIBLIOGRAPHY. Hofmann, G. De generatlone 

 et nsu partium, &c. 8vo. Altorf, 1648. Harvey, 

 Guil. Excercitationes de generatione animalium, 

 4to. Lond. 1651. Mcdpighi, De formatione pulli 

 in ovo, 4to. Lond. 1673; Ej. De ovo incubato, ib. 

 1686. Bartholinus, De form, et nutrit. foetus in 

 utero, 4to. Hafn. 1687. De Graaf, De virorum 

 organis generation! inservientibus, 8vo. Lugd. 

 Batav. 1668; Ej. De mulierum organis, ib. 1672. 

 Hartmann, Dubia de generatione viviparorum ex 

 ovo, 4to. Regiom. 1699, in Haller, Diss. Anat. 

 t. v. Trelincourt, De concepuone adversaria, 12mo. 

 Lugd. Batav. 1682. Garden, A discourse on the 

 modern theory of generation, Phil. Trans. 1691. 

 Taury, De la generation et le nour. du foetus, 

 Paris, 1700. Nigrisoli, Consid. intorno alia gene- 

 razione de viventi, 4to. Ferrara, 1712. Valisnieri, 

 Istoria della generaz. dell'uomo, Venet. 1721. 

 A. Maitre Jean, Obs. sur la formation du poulet, 

 2tno. Paris, 1722. Leuwenhoeck, in Phil. Trans. 

 for 1693, 1699, 1701, 1711, and 1723; Opera 

 om. 4to. Lugd. Batav. 1722. Brendel, De em- 

 bryone in ovulo ante conceptionem, Getting. 1740. 

 D. de Superville, Some reflexions on generation, 

 Phil. Trans. 1740. Bianchi, De naturali, &c. 

 generatione historia, Turin. 1741. Needham, 

 A summary, &c. on generation, Phil. Trans. 1748. 

 Buffon, Decouverte de la liqueur seminale, &c. 

 Mem. de Paris, 1748. Hatter, Ad Buffonii de 

 generatione theoriam adnot. in Ej. Op. anat. 

 minor, t. iii. Buffon, GEuvres de, t. i. and in 

 Mem. de Paris, an 1753. Parsons, Philos. ob- 

 serv. on the analogy between the propagation 

 of animals and that of vegetables, Lond. 1752. 

 Holler, De quadrupedum utero, conceptu et foetu, 

 in Ej. Op. anat. min. t. ii. Wolff", Theoria gene- 

 rationis, Halas, 1774. Spallanxani, Saggio d'osser- 

 vazioni microscopiche concernenti il systema di 

 generazione de Sig. Needham e Buffon, Modena, 

 1765. Memorie sopra i muli di varii autori, Mo- 

 dena, 1768. Sandifort, De ovo humano, in Ej. 

 Obs. pathol. lib. iii. Senebier, Experiences pour 

 servir a 1'histoire de la generation, &c. de Spal- 

 lanzani, &c. &c. Genev. 1785. Blumenbach, De 

 nisu formativo Comm. Gotting. vol. viii. p. 41. 

 Denman, Collection of engravings, Lond. 1787. 

 Zroeifel, Uber die Entwickelungstheorie, ein brief 

 an H. Senebier, Gotting. 1788. Mohrenheim, Nova 

 conceptus atque generationis theoria, Kb'nigsberg, 

 1789. Grasmeyer, De conceptione et fecundatione, 

 et Supplementa, Gotting. 1789. Speculations on 

 the mode, &c. of impregnation, Edinb. 1789. 

 Fontana, Lettera ad un amico sopra il systema degli 

 soilluppi, Firenze, 1792; Transl. intoReil's Archiv. 

 Band. ii. Haighton, On the impregnation of ani- 

 mals, Philos.Trans. 1797 ; Transl. in Reil's Archiv. 

 Bd. 3d. Ludwig, De nisu formativo, Lips. 1801. 

 Vicq d'Axyr, Anat. et phys. de 1'ceuf, in CEuvres, 

 t. iv. Pulley, On the proximate cause of impreg- 

 nation, Lond. 1801. Often,- Zeugung, Hamb. u. 

 Wurzb. 1805. Prevost et Dumas, Nouv. theorie de 

 generation, in Annales des Sciences Naturelles, 

 1825. The various systems of Physiology, but 

 especially Treviranus, Burdach, vol. i., and Hal- 

 ler's Elementa. 



( Allen Thomson.) 



* See John Hunter's well known paper on the 

 Free Martin in his Animal QSconomy, new ed. by 

 Owen, 1838. 



GLAND, Gr. aty ; Lat. Glandula; Fr. 

 Glande; Germ. Druse. 



An organ whose office is to separate from the 

 blood a peculiar substance, almost invariably 

 fluid ; constantly provided with an excretory 

 duct ; formed of a process of the mucous mem- 

 brane or of the skin, disposed either in the form 

 of a sac or of a ramified canal ; which sac or 

 canal in all cases is closed by a blind extremity ; 

 and which, although amply supplied with blood, 

 is never directly continuous with the bloodves- 

 sels.* It is absolutely necessary to give this 

 definite explanation of the meaning which is 

 attached to the -word gland in the present article, 

 inasmuch as there is no term in anatomy that 

 has been more vaguely, and as it appears to me 

 more incorrectly employed. 



It is not necessary to point out the absurdity 

 of applying this word to certain parts of the 

 brain, or to the masses of fat contained in the 

 joints, which were called by the older anato- 

 mists glands ; in these instances the fallacy is 

 immediately apparent; but there are other 

 errors which, although less striking, are, I con- 

 ceive, no less injurious in their effects. Thus 

 in the glandular system many continental au- 

 thorities include not only the liver, kidneys, 

 salivary glands, and other organs, which are 

 universally acknowledged to belong to this 

 class ; but likewise the lymphatic glands, the 

 thyroid, the thymus, the spleen, the supra-, 

 renal capsules, and the ovaries.f It is con- 



* The only real exception to this law is the testicle 

 of fishes, in which no excretory duct seems to exist. 



t Bichat, after condemning the application of 

 the term to the thyroid, the pineal gland, the 

 lymphatic glands, &c. states, " we ought only to 

 call those glands, which pour out by one or several 

 ducts, a fluid which these bodies separate from the 

 blood they receive by their vessels." Anat. Gen. 

 torn. ii. p. 598. 



Meckel, on the contrary, objects to the opinion 

 that an excretory duct is essential to a gland. Ac- 

 cording to his definition the glandular system com- 

 prises, 1. the muco\is glands ; 2. the sebaceous 

 glands ; 3. the liver, the salivary glands, the pan- 

 creas, the lachrymal glands, the tonsils, testes, the 

 ovaries, the prostate, Cowper's glands, the kidneys ; 

 4. the lymphatic glands, the thyroid, the mammary 

 glands, thymus, spleen, supra-renal capsules. 

 Man. d'Anat. torn. i. p. 511. 



It is surprising that so admirable a physiologist 

 as Meckel should adopt this opinion. 



Professor Miiller has also a classification, which 

 seems to me objectionable ; for he has admitted 

 among the glands the spleen, thyroid, lymphatic 

 glands, &c. It must not, however, be supposed 

 from this arrangement that this profound anatomist 

 considers these particular bodies as real glands. 

 His classification is as follows. (Handbuch der 

 Physiol. des Menschen, Coblenz, 1834, p. 418.) 



A. Ganglia sanguineo - vasculosa , the 

 spleen in the digestive organs the su- 

 pra-renal capsules in the genital and 

 uro-poietic viscera the thymus and 

 thyroid in the respiratory apparatus 

 glandula choroidalis in the eye the 

 placenta in the foetus. 



B. G. lymphatico-vasculosa , the lym- 

 phatic and mesenteric glands. 



Liver, salivary glands, testis, &c. 



