SCIENCE.

Lake County Press, Issue 2159, 7 March 1907, Page 7

SCIENCE.

- <*> WHICH IS YOUR HEALTHY SIDE, It is a curious fact, well known to tho medical profession, that ono side of tho body is ofteu healthier than tho other. Although an undoubted physiological fact, it is quite unexpliiinable, There aro many instances on record ou one side of tho body being absolutely paralysed, while tho patient has continued to enjoy good health for many years. Occasionally a patient who is on his deathbed loses all sensation in ono half of his body: circulation apparently stops, and thero is nothing to indicate that tho internal orgaus belonging to that half of the body aio performing their fuuetions. This phonomonou is quite distinct from paralysis, although it frequoutly happons that tbo life dies but slowly f.'om tho other half, and it imy bo many hours ere tho vital spark is finally extinguished^ Again, in soma instances ouo sido of tho body s.?eins healthier than the other all through life. Thus, ono oye is weaker than its fellow, and tho consequences of a cold in it may be much more nerious than tho other. A wound, too, ou tho healthier sido will heal rapidly, while that of the other may develop serious symptoms, It poems incredible that one half should be moro susceptible than the other, but it is £0 notwithstanding. f . i AMBULANCE; | Thero is yet. another subject of which tho ambulance student must know something in detail, before bo can bo expected to deal scientifically with fractures aud dislocations, and that is tbo muscular system and. its build. A considerable deal of dubiety exists among peoplo who have not studied physiology regarding tho muecular system. 'i'hey speak of 'muscles' without really knowing what a 'muscle" is, or what its exact functions in tho body aro. Nothing is easier than to comprehend tho nature of muscles, and also their mode of action, nd such knowledgo is essential for the studeut, because in cases of fracturo of bones and dislocations, as well as in tho case of other iujaries, muscles are always deeply involved. 'Muscle' is the ebiof flesh of an animal's body. Wo eat the muscle of tho ox when we consume a beef-steak. A mutton chop is tho 'muscloof the thu-p,' aud what we eat iu a fish is tho muscle of the animal. A good deal may be learn'id respecting muscles by looking at a cold roast of meat; Observe, first of all, that the flesh is not all iu one mass. Ou the contrary, it is divided into separate pieces, each of which is a ' musclo.' You can hoo whero ono musclo ends and another begins", as it wero, by looking at the divisions which n slico of the roast moat presents to view. Each musclo is separated from its neighbours by a thin, delicate layer, so that although tho muscles of a limb are beautifully packed together, it is easy to separate them by layer until the bone is reached.

Tho muscles give form and contour to tho body, and a sculptor must study carefully tho disposition of tho muscles in order to be able adequately and correctly to render the correct outline of the frame under its various aspects of sfilluess or movoment. We are besides familiar in ordinary life with certain prominent muscles of our bodies. Thus tho great musclo which forms the chief fleshy mass of tho upper arm is tho bicops; its function being that of bending the forearm on iho upper arm. The massatcr muscles are the great muscles of chewing, aud reach down each side of tho jaw. Then tho hip mufe'es which raise the leg in walking aro fami i.:: onough, and tho big muscles of tho :alf which raise tho heel are well-known. Tho ball of the thumb is a mass of muscles devoted to carrying out certain movements of that useful digit; while tho big fleshy mass in front of the thigh is composed of the great extensor musclo that straightens Ihe leg on tho thigh. j

Whenever wo fiud muscle wo know that its duty is to enable movement to bo performed. This is fhe function of muscle everywhere, and it is interesting to note in how many different regions of the body muscle is to bo found. Thus, first, wo find ull ordinary movements of grasping, walklug, leaping, and the like performed by tho muscles of arms and legs. Next, wo speak by »i;oans of tbo muscles of lip?, mouth, tongue, and larynx, or cbo organ of voice. Then we express our emotions by tho aij of muscles. A man who shrugs his shouldars, is an illustration of the latter fact. Tho blood is circulated by means of muscles; for the heart itself is a hollow musclo or rather a complex collection of muscles. Even the walls of tho arteries contain fine muscles which enable them to contract, and so to aid in tbo blood circulation. We digest our food partly by tho aid of muscles. Tho middle soafc of the etcmach is composed of muscles which by thoir contraction keep tho food moving wi*hin it. We chew our food by muscular aid, and wo swallow it by tho action of the muscles of thegullot, while tho walls of tho intestine or bowel contain muscles that propel the food along tho tube in the act of digestion. We broatho by aid of tho muscles of the chest, and oven tho fino air tubes of the lungs are provided with muscles. It is the sharp contraotion of these muscles which cause the spasm of asthma.

When wo come to consider the strueturo of muscles, we find tbo body's furnishing in- i eludes two distinct kinds of muscular tissue. | There is, first, the voluntary or striped muscles, which we can put iu notion when i wo like. These muscles are under the command of the will. They are represented by all the ordinary muscles of the body, and they are called 'striped' because under the microscopo wo see cross-striping on their fibres. The other muscles aro called involun- | tary or un6tripcd. They aio not under our ' command. They aro represented by tho muscles of tho walls ot tho stomach, by those of the blood vessels, by the muscle of tho pupil of tho eyo (which contracts or expands according to tho amount of light which plays on the organ of sight), and by other muscles in addition. Theee latter are called unstriped because they havo a different strueturo from the striped onea when tho microscopo is brought to hear upon them. Tho heart is tho only involuntary muscle in the body which has striped fibres. In some rospcots tho heart-muscles stand , midway between the two groups. A slice of cold roast meat, or a bit of boiled beef, shows us that each muscle is composed of bundles of fibres. Wo can separate out tho bundles easily enough, because they aro but loosely connected together. Each bundlo, in its turn, consists of fibres, and theso last can be teased out, under a low power of tho microscope, into smaller fibres or fibrils. Needless to say, muscles aro woll supplied with nerves and blood vessels. As active organs, they roceivo a largo supply of blood, and give off waste as tho result of thoir work. Tho heat of tho body, also, is largely generated in tho muscular system. Each muselo consists of a fleshy part (the belly) and of a tendon, or sinew, at each end. By means of the tendon, tho muscle is firmly attached to tho bones it is destined to move. The tendon, as a tough structure, obtains a firmer grip of the bono, as it were, than would bo tho case if the attachment took place directly by means of the fibres of the flesh. Tho actual movement, of course, takes place in tho fieehy part of tho mußclo. We may gain a good idea of sinews, or : tendons, b/ looking at tho back of tho hand. We can see tho tendons moving when wo extend our fingers. These aro tho sinews which run down to the fi D gers ; the muscles themselves, are situated io the back of the fcrearm. Allmusoles aiove tho part to which they

are attached because they possess a property called contractility. Put in plain English, this ineans that muscles possess a power of shortening themselves; and when thoy shorten they pull together tho parts they connect. The impulse which puts muscles in action comes from the brain aud nervous system. The nerve excites the muscle ,to action ; or, in the caso of the involuutary ones, they aro excited directly by some stimulus, such as food eutering the stomach, or by light falling ou the eyo in the case of tho pupil muscle. If you place your hand over the biceps muscle of ono arm, keeping your arm straight, and then bend the forearm, you will find the biceps grow shorter and thicker under your toucn. Now, a muscle moves at one end only. This is called its insertion. The other and fixed end is called its origin. In tho case of the biceps, tho origin is at tho shoulder, while tho insertion is in tho radius bone of the forearm. Wo therefore see that if tho shoulder end remains fixed, and tho other or radius-end movos, tho muscle, when it grows shorter, mnst pull the forearm noarer tho upper arm. All muscles act in ibis way. Different groups of mußcleß in the body oppose ono anothor. Thus, the muscles which closo tho fingers aro placed on tbo front of tho forearm, while thoso that open tho fingers aro placed on the back of the same region.