530 



MUSCULAR SYSTEM. 



nis mwsculosre structure, Lugd. Bat. 1730. In- 

 vestigatio fabrics, quse in partibus musculos 

 component, extat. Lugd. Bat. 1741. Borelli, 

 De motu animalium. Ed. Neapoli, 1734. Cowper, 

 Myotomia Reformata. Introduct. Haller, Ele- 

 ment. Phys. lib. xi. Hales, Statical Essays, Lond. 

 1741. Prochaslta, De carne muscular!, Vindobon. 

 1778. Fontuna, Traite sur le venin de la vipere, 

 Flor. 1781. J. Hunter, Croonian Lectures, 1781, 

 Works by Palmer, vol. iv., notes by Owen, Lond. 



1838. G. R. Treviranus, Vermischte Schriften, Gb'tt. 

 1816, Beitrage zur Auf klarung, &c. P. Mascagni, 

 Prodromo della grande anatoinia, Firenze, 1819. 

 Home and Bauer, Phil. Trans. 1818 and 1826. 

 Milne Edwards, Memoire sur la struct, element. 

 &c. Paris, 1823 ; Ann. des Sciences, 1826. Pre- 

 vosl & Dumas, Majendie Journal de Physiologie, 

 1825. Hodgkin and Lister, Appendix to a Trans- 

 lation of W. F. Edwards " on the Influence of Phy- 

 sical Agents on Life-," and Annals of Philosophy, 

 1827. Valentin, Histor. evolutionis syst. muse, 

 prolusio. Wratislav. 1832 ; Ueber den Verlanf und 

 die letzten Enden der Nerven. F. C. Emmert, 

 Ueber Endigungsweise der Nerven in den Muskeln, 

 Bern. 1836. E. Burdach, Beitrag znr Mikrosko- 

 pisch. Anatomie der Nerven, Konigsburg, 1837. 

 Roulin, Majendie Journal, vol. i. G. H. Meyer, 

 Diss. Inaug. de Muscul. in duct, efferent, gland. 

 Berol. 1837. Krohn, Muller's Archiv. Jahrg. 1837 ; 

 Heft. 3, 4 ; Brit, and For. Med. Rev. Ap. 1838. 

 Ficinus, De fibrae musculaiis forma, et structura, 

 Lipsi, 1836. Schwarm, in Muller's Physiology 

 by Baly, Lond. 1837-41. Baly, in the same, pt. iv. 

 description of plate. Lauth, L'Institut, No 73. 

 Skey, Phil. Trans. 1837. Malgaigne, Anatomie 

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 Traite Pratique du Microscope, Paris, 1839. Gul- 

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1839. Henle, Allgemeine Anatomie, Soemmeririg, 

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 1839-40-41-42. Bowman, Phil. Trans. 1840-41. 



( W. Boivman.) 



MUSCULAR SYSTEM, (COMPARATIVE 

 ANATOMY OF). The muscular system of ani- 

 . mals, as the term is generally understood, is 

 composed of masses or fasciculi of highly irri- 

 table filaments, by the contractions of which 

 the movements of the body, whether voluntary 

 or involuntary, are effected, and the arrange- 

 ment of these moving powers, their size and 

 strength, forms and general disposition, must 

 of course vary ad infinitum in the different 

 classes of animals, in conformity with the varie- 

 ties of their external form, or the innumerable 

 kinds of apparatus conferred, for special pur- 

 poses, upon particular tribes or even species of 

 living beings. Of these detailed accounts are 

 elsewhere given in those articles which treat of 

 the structure and anatomy of each class entering 

 into the composition of the animal kingdom. 

 Nevertheless, it has been deemed advisable, 

 upon the present occasion, to collect together 

 in one view the principal facts connected with 

 general myology, and to state, as briefly and 

 concisely as the nature of the subject will 

 allow, those grand physiological points which 

 an extended review of the comparative organi- 

 zation and development of the muscular system 

 reveals to the anatomical observer, in order to 

 concatenate the leading facts recorded in other 

 pages of this work. 



It may be laid down as an axiom universal 



in its application, that the condition of the 

 muscular system in any race of animals must be 

 dependent upon, or at least in strict conformity 

 with, the development of the nervous apparatus, 

 by the influence oj' which muscular movements 

 are excited, controlled, directed, a?id associated. 

 Thus, as we advance from lower to more 

 elevated forms of living creatures, it is easy to 

 perceive that in exact proportion as the nervous 

 system makes its appearance, and becomes pro- 

 gressively more elaborately organized, the mus- 

 cles themselves become developed and assume 

 a perfection of structure and precision of move- 

 ment adapted to the increasing exigencies of the 

 animal economy; nay,ithas now been satisfacto- 

 rily established that even among the highest races 

 of the animal creation, during the progress of 

 embryo development, the most intimate relation 

 is observable between the state of the nervous 

 centres and the condition of the nascent muscles 

 as they become gradually formed and perfected. 

 In the lowest Zoophytes where nervous fibres 

 of any kind are not perceptible, even under the 

 most rigid microscopical examination, the con- 

 tractile tissue of the body is equally diffused 

 and devoid of aggregation into filaments or 

 fasciculi of muscular fibre, and precisely under 

 the same conditions the first rudiment of the 

 vertebrate embryo, being as yet entirely devoid 

 of nerves, is also destitute of distinct mus- 

 cles, the movements of which could only be 

 associated and rendered efficacious by means of 

 nervous intercommunication; and this com- 

 plete want of aggregation of the elements of 

 muscular tissue is as remarkable throughout all 

 the Acrite division of the animal world as it is 

 in the nervous matter entering into the compo- 

 sition of their bodies, which, although its pre- 

 sence is not to be detected by our senses, is rea- 

 sonably supposed to exist in a diffused state 

 even in the lowest tribes of animated beings. 

 As soon as nervous threads become apparent, 

 and long before ganglionic masses of neurine 

 are developed to such an extent as to entitle 

 them to be regarded as centres of innervation, 

 the muscular tissue, in like manner, assumes a 

 different and far more perfect character ; the 

 elementary molecules composing muscular fibre 

 are then distinctly visible, and assuming a defi- 

 nite arrangement become grouped in longitu- 

 dinal series, exhibiting contractile bands and 

 fascicles placed in precise directions, and capa- 

 ble of effecting movements of a more decided 

 character than could possibly be exercised in 

 creatures deprived of nervous cords, whereby 

 the contractions of numerous muscular fasciculi 

 might be associated and made to cooperate for 

 the accomplishment of a given purpose. 



Moreover, it must be obvious that, in that 

 great division of the animal creation which is 

 characterized by the existence of nervous fila- 

 ments, the ganglionic centres being as yet 

 imperceptible, or at least where any have been 

 detected, in a very rudimentary state of de- 

 velopment (the NEMATONEURA of Professor 

 Owen); such a condition of the nervous appa- 

 ratus involves, as a necessary consequence, 

 important circumstances connected with the 

 general economy of the beings so organized as 



