Volume 1

Science for all / edited by Robert Brown.

Date:: [1877?-1882?]

Credit: Science for all / edited by Robert Brown. Source: Wellcome Collection.

383/408 page 367

$tlie albumen of the otLcr are converted into the Obrin of which our Hesh is built up. The cereal irrains dexive their value from anotlier modification of fibrin, called gluten, which any one can obtain hj the simple process described on page 272. In the human body gluten is also converted into muscle; so that we have three flesh-forming principles, similar in chemical constitution, but difi'ering in physical properties. Thus, albumen coagulates by heat, but fibiiu coagulates spontaneously as soon as it is withdrawn what has it to do with the dinner-table 1 Well, if you are fond of roast beef, you are fond of the muscles of the ox; or, if you are partial to sole or salmon, you appropriate the muscles of those fish; so that every piece of lean, fibrous flesh brought to table—whether procured from the butcher, poulterti-, or fishmonger—is a bundle of muscles. We are all familiar with the muscle of the human arm, and its power of contractility. If we grasp the arm tightly above the elbow, and move the hand towards the head, we shall feel a resistance; because by thi( Fij. 1.—Red Corpuscles of the Blood of vauiods Vertebrate Animals. Hi Red Corjiuscles of Human Blood Imprisoned by the Fibrin in Coagulated Blood; (2) Globules of Human Bl iod gathered in Bolls ; (3) Globules of Human Blood in Bi-concave Oirculnr Disrs; (4) Globules of Camel's Blood in Elliptical Discs: (5) Globules of Pigeon's Blood, Elliptic Bi-convex Discs 16) Prog's Blood, Elliptic Discs; (7) Loach's Blood, rounded; (8) Blood of Salamander; (9) Blood o£ iepidosirfm, Bi-concave rounded Discs •, ClO^ Blood of Proteus. ^^^^^ ^^.^^ G\o^,^Ae^ ■ (!,) Side View. from the fluids which keep it in solution. In the blood the fibrin is dissolved by the alkaline salts— that is, the salts of soda and potash—present in the ssrum; s© tliat, although these salts exist in a|:)parently trifling proportions, if they were with- drawn fi'om the system the fibrin would immediately coagulate, and the blood would cease to flow. This phenomenon actually occurs after death, and in some diseases just before death. Fortunately, there are few articles of diet, whether animal or vegetable, that do not contain more or less of these valuable salts; and when we come to speak of vegetables we shall notice them more in detail. It has been stated tliat fibrin is the build- ing material used in the construction of the muscles of all animals. Now the question arises, What is muscle; and movement the muscle, which is attached by tendona at one end to the bones of the wrist, and at the other to the shoulder, becomes shortened, and must there- fore increase in diameter. What is here related of the function of one muscle will apply with equal force to all otlier voluntary muscles. They are the organs by which motion in any part of the body is accomplished. We cannot walk, run, laugh, sing, or perform any kind of manual labour -without calling into action various sets of muscles. There are mixscles, such as the heart, which per- form work independently of the will. These are called involuntary muscles, and they do not pre- sent the same fibrous structure as the voluntary muscles. If we examine a muscle of the first class, we shall see that it consists of a number of fibres rimning in a parallel direction from one end to the$

Science for all / edited by Robert Brown.

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