Licence: Public Domain Mark
Credit: The anatomy of the human body / By J. Cruveilhier. Source: Wellcome Collection.
Provider: This material has been provided by the University of Massachusetts Medical School, Lamar Soutter Library, through the Medical Heritage Library. The original may be consulted at the Lamar Soutter Library at the University of Massachusetts Medical School.
218/944 (page 194)
![pale ■* still less is it so in the lower animals, some of which have the entire muscular system perfectly colourless. The red colour of the muscular fibre is independent of the blood contained within the vessels of the muscle. 2. Consistence.—The consistence of the muscular fibres varies in different subjects : in some it is soft and easily torn ; in others it is firmer and more resisting, and retains for some time after death a degree of rigidity which yields with difficulty to forcible ex- tension. Structure.—The muscles may be divided into bundles or fasciculi of different orders, and these, again, into distinct fibres, wliich are visible to the naked eye, and rendered more apparent, either by dissection, or by the action of alcohol, of diluted nitric acid, or even of boiling water. They are of a variable shape, resembling prisms of three, four, 'five, or six surfaces, but are never cylindrical. Their length also varies in different muscles, in but a few of which do they extend parallel to each other tliroughout the en- tire length of the fleshy belly. Each muscle is surrounded by a sheath of cellular tissue, which also penetrates into its substance, and surrounds both the fasciculi and fibres. Tliis cellular tissue permits the free motion of the different fasciculi upon one another, while it serves, at the same time, to isolate each and combine the whole.t The chemical analysis of muscular tissue shows that it is composed of a small quan- tity of free lactic acid (Berzelius); gelatin; some salts; osmazome in greater or less quantity, according to the more or less advanced age of the individual; and leucine, a substance extracted from this tissue by the process described by M. Braconnot. (Ann. de Chim. et de Phys., tom. viii.)1: In addition to the tendinous and fleshy fibres, vessels, nerves, and cellular tissue also enter into the composition of muscles. We have already described the disposition of the cellular tissue contained in these organs; the mode of distribution of their vessels and nerves will be more appropriately alluded to in the description of the vascular and ner- vous systems, ij Uses of Muscles. The muscles are the active organs of motion, constituting the source of the power * [The involuntary muscular tissue, of which the above-named fibres afford examples, are, with the excep- tion of the heart, of a much paler colour than the voluntary muscles, to which this division, of the present work exclusively refers.] t [In reference to the microscopic structure of the voluntary muscles, or those of animal life, it has been ascertained that the smallest fasciculi (C(irresponding with the prismatic fibres of our author, and with the -secondary fasciculi of .MiJller), the size of which varies in different muscles, are divisible into transversely-slri- ./aUdfibres (the primitive fasciculi of Miiller), having a uniform diameter in all muscles in the same species, and being themselves composed of still smaller elementary parts na.meii filaments (the primitive fibres of Miil- ler), All these elements of the muscular tissue extend parallel to each other, from one tendinous attachment :to aaother, never having been seen to bifurcate or coalesce. In .man Ihe fibres vary from xATjtli to -g-^-gth of an inch in diameter; the trans\-erse striiE upon them are parallel, generally straight, b Jt occasionally slightly waved or curved ; they are situated at intervals of from . Jl ^ tfa to y-o g-Q^th of an inch. The f.laments are varicose or beaded, i. e., alternately enlarged and contracted ; their diameter is from .1 th to —^-—th of an inch. According to the general opinion, thev are held together in each fibre by 1g 0001^000 means of a glutinous substance, which latter, according to Skey, constitutes the entire centre of the fibre, the circumference alone being occupied by the filaments. In the lan-ie of insects, a delicate membranous sheath, sometimes observed projecting beyond the filaments, has been described by Schwann as forming a proper in- vestment of the fibre ; and, by analogy, this is also presumed to exist in man and the other vertebrata. Be this as it may, it is certain that the fibres have no separate sheaths uf cellular tissue derived from the common gheath of the muscle, the prolongations of which appear to extend only so far as to enclose the smallest fasciculi. The cause cf the striated appearance has, perhaps, not been quite satisfactorily ascertained ; but since the enlart'ements on the varicose filaments are darker than the constricted portions, and since ihey are situated at intervals precisely similar to those between the transverse stris of the corresponding fibre, and from some other additional considerations, it has been supposed, with great probability, to result from the enlarged and dark portions of the filaments being arranged side by side. For an account of the microscopic characters of the involuntary or organic muscular fibres, .see the notes on the structure of the several viscera, &c.,in which they are found, viz., the alimentary canal, trachea, genito- nrinary organs, and iris. We may remark here, that the muscular fibres of the heart and of the upper part of the oesophagus are striated, and approach very closely in character to those of animal Ufe.] t [The following analysis of the muscles of the ox is on the authority of Berzelius . Water 77-17 Fibrin (with vessels and nerves) 15.8 Cellular tissue convertible into gelatin . . . . . 19 Albumen and colouring matter 2'2 Alcoholic extract, or ozmazome, with lactic acid and lactates 1'8 Watery extract, with phosphate of soda ..... 1'05 ;Phosphate of lime '08 100- The inadvertent omission, on the part of M. Cruveilhier, of ^irin as one of the proximate principles of mus- cle will serve to impress on the mind of the reader its importance as a constituent of that tissue, in which it exists in greater abundance than in any other. The substance called leucine, mentioned in the text, is a product resulting from the action of concentrated sulphuric acid on muscular fibre, and therefore must not be regarded as previously existing in it.l 6 As it is our intention to introduce, after Myology, an account of the Aponeuroses, we shall be content at present with the general ideas that have been already stated regarding this important division of the fibrous tissues.](https://iiif.wellcomecollection.org/image/b21196801_0218.jp2/full/800%2C/0/default.jpg)
