INFLAMMATION PERTAINING TO ZOOLOGY.

Clutha Leader, Volume III, Issue 151, 1 June 1877, Page 7

I N FL AMMATION PERTAINING TO ZOOLOGY.

When a part such as the white, of the eye becomes red hot, painful, and swollen, it is said to be in a stale of inflammation. It mmy be excited in any part of the surface, and it may also attack any internal organ. Hence inflammation is the most common disease of all the most fatal with which we have to contend. I am going to give you a very short account of inflammation, more particularly pertaining to its nature. In order to arrive at the phenomena of inflammation, it will be necessary to examine with the microscope the web of a frog's foot, which, from its transparency, the various processes can easily be perceived both in its healthy state ana when irritated. Jf you place the web of the living- frog under the microscope, and bring the focus to bear upon one of the arteries, you will observe the blood rushing along* in a very rapid state, and if you follow it up it will break up into numerous small vessels of uniform size, and here it loses its impetuosity, which enables you to see the different constituents of the fluid, which is made up of red and colourless corpuscles. Arteries under ordinary circumstances possess a- certain size ; they are capable of enlarging- to a certain extent from the quantity of blood which is sometimes thrown upon them, but when, the blood again resumes its natural course the artery subsides to its original size, if now we gently irritate the artery, it immediately contracts, and the circulation is either impeded or brought to a standstill. This, however, is soon followed by dictation, and the blood rushes through in greater quantities with greater rapidity than usual, and in a short time the' artery resumes its natural size prior to the experiment. Here we have no inflammation ; the irritation merely excited the artery to contract. If now the artery be irritated irove strongly than before, additional phenomena ensue, which we recognise as inflammation. The artery dilates immediately, and the blood rushes on with greacer velocity and gorges the capillaries ; soon, however, the circulation becomes slower and slower, until it comes to a standstill. On examining the corpuscles in this irritated or inflamed state, we find that they have a remarkable tendency to adhere to each other, or to the vessels, and there is no doubt that is the immediate cause of the stoppage of the circulation, and when this is stagnant in the inflamed part, more is continually arriving, being propelled forward by the action of the heart, and in consequence the capillaries become distended with blood corpuscles, which usually form pouches in the capillaries, and sometimes, owing to the great pressure of blood, burst, and allow the blood to become exlravasated in the surrounding tissue. So as to understand the nature of the alteration which takes place in the texture of a part about to become inflamed, it will be necessary to notice the remarkable movements which are made in certain cells called pigment cells. These are distributed in great numbers in the substance of the true skin, and are situated also on the walls of the blood vessels. On examining them they are seen to be black bodies, consisting of a central portion, from which processes of various size radiats. These pigment cells contain a colourless body called the nucleus, and likewise a colourless fluid in whish float an immense number of minute particles which present a coal-black appearance. If now we irritate strongly a small portion of the web of the frog's foot, by placing a drop of turpentine or mustard on it, we shall see a difference in the behaviour of those pigment cells under the irritant and those at a little distance. On continuing to watch these cells situated at the point of the irritant, they remain in the same state, while the surrounding ones exhibit movements of their molcules as usual. The movements of those under the irritant are destroyed by its acting, so as to paralyze the central force. If, however, the irritant has not been too great nor too long applied, the cells recover, and it again exhibits its usual movements ; at the same time the part begins to swell from the formation of fibrin and the effusion of serum, and the various signs of inflammation ensue. And what takes place in the pigment cells likewise takes place in the others ; so that the first stage of inflammation consists in paralysis of the part. When the irritant has been so great as to cause permanent paralysis of the pan then mortification or death of the part ensues. When the irritant has been more gentle, the part resumes after a time its functions, but in a disordered manner, so as to give rise to various orders of inflammation. When it has boen light the reactionary phenomena will be correspondingly mild, while, if the irritation has been severe, suppination, ulceration, etc., will take place, and the structure of the part will be destroyed to a greater or less extent. When n part has been irritated to cause temporary paralysis of its function, it is easily discerned in exteral parts by the latter becoming hot, «d, painful j' ami swollen, so that heat, redness, pain, and swelling have always been regarded as certain signs of inflammation. It must not be forgotten, however, that one or more of these signs may be absent, or when present, as for example, in inflammation of internal organs. The

intensity of these siutjs vnrv considerably in inflammation of different parts. Sometimes swelling is the prominent symptom, us in parts which possess considerable quantity of loose tissue, viz, the scrotum and eyes ; at other times, pain, as in inflammation of internal organs. Of the four signs perhaps pain is, the most important, for in this way attention is directed to the parr. Pain of itself does not indicate that the part is in a state of inflammation, but when accompanied by other local signs which i shall point out, and by general constitutional disturbances, it is a reliable sign of inflammation. Pain varies according to its seat, degree, and stage of the inflammation : culling or lancing in inflammation of the serious membranes ; dull gnawing in inflammation of bones ; and burning in inflammation of skin. When pus or matter forms the pain becoaies throbbing. With regard to the heat of an inflamed part, it is never so as it appears to the touch. However hot the place may feel, it is never in reality more than two degrees above the ordinary temperature of -the blood ; it is caused by an unusual quantity and a more rapid flow of blood through the part.^ It follows that the more intense the inflammation is the more heat will there be. With reference to the redness of an inflamed part, it is due to a larger quantity of blood being present than in health, and the capillaries owing to the great pressure upon them by the blood, give way, and the blood becomes diffused in the surroundingtissue. With regard to the swelling, it is cause i by the effusion of serum and formation of fibrin in the part which is the albumen of the blood. When the fibiin is formed the swelling is hard and unyielding. The hard part of the swelling is always the true seat of the inflammation, and occupies the centre. There the pain, redness, and heat 13 most intense, while the surrounding soft portions give rise to little or no disturbance. At; first you can generally divide it into two portions, hard and soft, and the softer portions in general pass into the neighbouring healthy textures. Soon, however, pas or matter begins to form, and this take.-? place in the centre of the hard swelling. It may be said that three distinct portions are observable, viz., first, a central soft part; second, a hard unyielding ring immediately surrounding "number one; and thirdly, a soft diffuse swelling which pits on pressure. After a certain time the central soft portion becomes elevated at a particular place, usually the centre, and the abscess is then said to point. This is the result of the effort wnich the pus makes to escape, and if the' process be not interfered with an opening is made through which the pus will escape. When inflammation has been set up in a part, it may terminate in one of the following — resolution, suppuration, ulceration, or mortification, which 1 will deal with in my next paper, along wilh the treatment on inflammation.