410 GENERAL ANATOMY. 



In his time a voluntary contraction more prompt and more 

 extensive than this contraction by elasticity was also admitted. 

 At the epoch of the revival of the sciences, myology was 

 still in the very imperfect state in which it had been left by 

 Galen; it is indebted to James Dubois (Sylvius] for consider- 

 able advancement: he named most of the muscles, which had 

 previously taken place only with respect to a very small num- 

 ber of them. Vesalius, and the other anatomists of the Italian 

 school, Eustachi especially, have perfected the knowledge of 

 the muscles, and have figured them. The intimate texture of 

 the muscles, their contractile action, the nervous influence of 

 this action, and the movements which result therefrom, have 

 been sedulously studied during the course of the two last cen- 

 turies, and are still the subject of important labours.* 



651. In the more simple animals, the muscular fibre is not 

 distinctly perceived: in them movements are produced by the 

 cellular tissue. In the first of the series where the muscular 

 fibre appears, it only moves the tegumentary membranes to 

 which it is annexed or of which it forms a part. In all those 

 which possess a heart, this fibre is the principal element of 

 this organ. Lastly, in the vertebrate animals, a few muscles 

 only are attached to the mucous membrane, to the skin, and to 

 the senses, their dependencies; a great number, on the contra- 

 ry, are attached to the skeleton, in order to move it. 



652. In man there are two classes of muscles: the first, 

 interior, membraniform and hollow, appertaining to the mu- 

 cous membrane and the heart, contracting involuntarily, and 

 subservient to the functions of nutrition and of generation, in 

 a word, to the vegetative functions; the second, exterior, 

 more or less thick and full, belonging to the skin, to the senses, 

 to the skeleton, and to the larynx, contracting voluntarily and 

 subservient to the animal functions. Both classes present 

 characters common to each other, which it is necessary to 

 consider generally. 



Messrs. Prevost and Dumas are making observations on the intimate 

 texture of muscles and on muscular action. They have had the goodness to 

 communicate to me the first results, as yet unpublished. 



