the diagonal of a parallelogram of which the sides are represented by the 

 muscles in action. 



CLXIX. Of the nature of muscular flesh. I shall not speak, at present, 

 of the manner in which the muscles receive nourishment, by retaining 

 within the meshes of their tissue, the fibrina which the blood conveys to 

 them in such quantity, that several among the ancients and moderns have 

 called the blood, " liquid flesh ;" an expression at once forcible and cor- 

 rect, since all the organs are repaired and grow, by the solidification of its 

 different parts. Haller first observed that most of the muscular arteries 

 were very tortuous in their course to the muscles. This disposition, 

 which cannot fail to slacken, very considerably, the course of the blood, 

 favours the^ formation and the secretion of the fibrous element which the 

 muscles appropriate to their own substance, and to which it bears so 

 strong an affinity. Motion influences, in a very remarkable manner, this 

 nutritive secretion. The muscles that are most in action, uniformly 

 acquire the greatest size and strength ; if left in a state of complete inac- 

 tion, they become exceedingly reduced in size, from the suspended secre- 

 tion of the fibrinous principle. Muscular motion promotes, very remark- 

 ably, the circulation and the distribution of all the fluids. The flow of 

 venous blood, after bleeding, is never copious, unless the muscles of the 

 fore arm are made to contract, by making the patient hold the lancet case, 

 and desiring him to move it round his hand. , 



The chemical nature of the muscular fibre is nearly the same as that of 

 the fibrina obtained from the blood*. Like the latter, it contains a great 

 quantity of azote, and is, consequently, very much animalized and ex- 

 ceedingly putrescent. It is from muscular flesh, that M. Berthollet ob- 

 tained, in considerable quantity, the peculiar animal acid, called by that 

 chemist, the zoonic acid^. Lastly, the element of the blood, by means of 

 which the muscular flesh is repaired, fibrina, is already imbued with vital 

 properties, even while it yet flows in a state of combination with the other 

 parts of the fluid. This fibrina, extracted from the blood and subjected 

 to the galvanic influence, is distinctly seen to quiver and contract under 

 that influence. At what period does this substance acquire the power of 

 contracting-? It is, doubtless, at the moment when it becomes organized, 

 in passing from the fluid to the solid state. What relation does there 

 exist, between the organization of matter and the vital properties with 

 which it is endowed? This question cannot be answered, in the present 

 state of our physiological knowledge:}:. 



CLXX. Galvanism. A Professor of Anatomy in the University of 

 Bologna, Galvani, was one day making experiments on electricity. In 

 the laboratory, not far from the machine, lay some skinned frogs, of which 



* Nothing 1 can prove, in a more complete manner, the essential difference between 

 the fleshy parts of muscles and their tendinous and aponeurotic parts, than the chemical 

 analysis of these organs. The tendons and aponeuroses may be completely resolved 

 into g-elatine, by long boiling 1 , which, on the contrary, parches the muscular flesh, by 

 exposing 1 the fibrina, in consequence of the melting of the fat of the cellular tissue, and 

 of the albuminous juices in which it is enveloped. See the Chapter at the end of the 

 APPKSBIX, on the Chemical Constitution of the Animal Textures and Secretions. 



j" Another secretion which is obtained abundantly from muscular tissues, and denomi- 

 nated osmazome by modern chemists, may be noticed. It appears to be a species of 

 animal extract, of a brown colour, aromatic, and very nutritious. It gives soup its savour, 

 and forms a great proportion of the gravy of meat. Although osmazome is an animal 

 product, it is found on analysis in some species of mushrooms. 



T See APPENDIX, Note F F. 



