The farmer's veterinary adviser, a guide to the prevention and treatment of disease in domestic animals

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UNITED STATES OF AMERICA.

Preface

This work is especially designed to supply the need of the busy American farmer who can rarely avail himself of the advice of a scientific veterinarian. The author is deeply sensible of the low estimate placed upon Veterinary Medicine and Surgery in the United States, and the necessity of educating the public up to a better appreciation of its value. We have a property in live stock estimated at $1,500,000,000, and rapidly increasing in value, consisting of at least six different genera of mammals, besides birds, and therefore affording an almost unlimited field for the practical exercise of humanity, political economy, and scientific research in the pursuit of Veterinary Medicine. In the Old World millions are saved yearly to each of the Western European Nations in the exclusion and extinction of animal plagues, and many instances can be adduced of an intelligent veterinary supervision saving at the rate of $30,000 per annum on a stud of 400 horses. But in the Western Hemisphere, apart from the larger cities, the great pecuniary interest in live stock is largely at the mercy of ignorant pretenders, whose barbarous surgery is only equaled by their reckless and destructive drugging. The constantly recurring instances of absolute and painful poivi Preface.

soning, and cruel and injurious vivisections practiced under the name of remedial measures are almost sickening to contemplate. To give the stock-owner such information as will enable him to dispense with the unprofitable and perilous services of such pretenders, and to apply rational means of cure when he happens to be beyond the reach of the accomplished veterinarian, is the aim of this book, and this, it is confidently hoped, it will accomplish for all who will intelligently study its pages.

To secure this object, and yet to place the book within the reach of all, it was necessary to sacrifice all extended discussion of diseased processes, and questions in pathology, and therefore the reader who may discover deviations from current opinions is requested to suspend his decision until he has consulted the Author's larger work, in which the reasons for these positions will be given.

With this view of still further condensing the work, the doses of medicines for the different animals are rarely given in the text, but one or more agents are named as applicable to every distinct stage or phase of the disease and species of patient, and the reader must turn to the list of drugs given at the end to find the amount required for each animal. In doing this he must note particularly for what purpose the agent is given and select the dose accordingly, as the effect of large doses is usually essentially different from that of small ones. Thus common salt given in large doses to cattle is purgative and reducing, while in small ones it is alterative and tonic. Sulphur in large doses is laxative, but in small ones alterative, expectorant, and diaphoretic. Oil

Preface. vii

of turpentine in large doses is purgative and vermifuge, in small ones diuretic, stimulant, and antispasmodic. Attention must also be given to the age and size of the patient, as more fully set forth in the Appendix.

Illustrations have been freely introduced to render the text more lucid, and, being selected from those prepared for the Author's larger work, may be implicitly relied on.

In the list of contagious diseases are included not only those that are habitually developed on American soil and those already introduced from abroad, but also such as prevail in Europe, and are liable at any time to be brought into our midst by importation. It is no less imperative that the American farmer should be forewarned of pestilences that threaten him from abroad, than of those that beset him at home. For all such affections the principles that should guide us in preventing and extinguishing the disease are concisely but clearly set forth.

All the important parasites are introduced, and their conditions of life and individual metamorphoses in and out of the bodies of domestic animals referred to, as well as their migrations from man to animals and from animals to man wherever such exists. The vast importance of animal parasites is only beginning to be realized in connection with their frightful ravages in countries (England, Australia, Buenos Ayres, Egypt, Abyssinia, Iceland, India, etc.) into which they have been introduced, or where they have been allowed to increase unchecked, and a concise statement of their forms, habits, and results is therefore imperatively necessary for the protection of the stock-owner.

viii Preface.

This subject has accordingly been brought up to the date

of present observations, and though short enough for the

perusal of the busiest, it will furnish a sound basis for

the limitation and destruction of each of these noxious

pests.

JAMES LAW,

Cornell TJnwersity.

Ithaca, May, 1876.

Contents

Inflammation and Fever, .

Contagious and Epizootic Diseases, .

Specific Contagious and Epizootic Diseases, Larger Parasites, ....

Chapter I. Inflammation And Fever

Inflammation. Its phenomena. In vascular tissues. Changes in blood-vessels ; in blood ; in cells ; in tissue ; in function. Exudations. Migration of globules. Reparatory processes. Inflammatory fever. Inflammation in non-vascular tissues. Deranged nutrition ; cloudy swelling ; exudations ; cell multiplication ; cell migration ; formation of blood-vessels ; purpose of cell multiplication. Exudations and effusions — serous, mucous, fibrinous, bloody, croupous. Results of inflammation. Resolution. Delitescence. Metastasis. New formations, plastic, aplastic. Suppuration. Pyogenic bacteria. Pus, cells, liquid. Abscess, acute, chronic. Diffuse suppuration. Fistula. Healing by first and second intention. Granulation. Granule corpuscles and masses. Development of lymph into tissue. Degenerations of new growths. Softening. Ulceration. Death by molecules. Gangrene ; death of a part. Fever ; definition ; stages ; symptoms ; premonitory ; chill ; reaction ; defervescence, crisis, lysis. Temperature in health and disease. Retention of water in system. Tissue waste. The typhoid condition. Types of fever. Treatment of inflammation and fever. Regimen. General fever remedies. Bleeding — general, local ; leeching, cupping. Warm baths — in chill and hot stage. Cold baths. Diaphoretics. Laxatives. Diuretics. Sedatives. Alkalies. Tonic refrigerants — in convalescence ; in typhoid states. Local treatment of inflammation — cold, astringents, antiseptics, hot applications. Stimulating embrocations and lotions. Blisters. Firing. Treatment of abscess.

INFLAMMATION.

Inflammation forms the essential part of so many diseases, and a concomitant of so many more, that a brief statement of its features and phenomena appears desirable, even in a

The Farmer's Veterinary Adviser.

condensed manual like the present. From the days of Hippocrates inflammation has been recognized by redness, heat, pain, and swelling, followed by resolution or induration, suppuration, or gangrene. Such a definition is, however, sadly insufficient in view of modern discoveries as to the different phases of the inflammatory process. Redness occurs in the transient blush, heat in the feverish system, pain from simple passing nervous disorder, swelling from dropsy, induration from the formation of tumors, and gangrene from the blocking of blood-vessels or other exclusion of blood and the means of nutrition from a part, and in no one of these cases need there be an element of true inflammation. Perhaps no definition can be given which will cover all the phenomena of inflammation.

INFLAMMATION IN VASCULAR TISSUES.

These phenomena, as seen in a transparent membrane like the web of the frog's foot or the mesentery may be stated as follows : 1st. Disturbed circulation evinced by contraction, quickly followed by dilatation with elongation of the capillary blood-vessels, and a rapid, followed by a slow, and even oscillating or backward movement of the blood within them, branching redness. 2d. The blood-globules become sticky and adhere together and to the walls of the capillaries so as to block them in points. 3d. The fibrin of the blood coagulates around these masses of globules, forming points of complete obstruction, and constituting those minute spots of deep redness which cannot be effaced, even for an instant, by the pressure of the finger on inflamed skin. 4th. The liquid parts of the blood ooze out in excess through the capillary walls into the tissues, causing the swelling. 5 th. Blood-globules and granules escape through the walls of the vessels and degenerate into pus-cells or become the centres for the growth of new tissue in the exudate. 6th. The nuclei {cells) presiding over the nutrition, etc., have

Inflammation and Fever.

their functions impaired or lost ; the inflamed skin in the frog has its pigment-cells unchanged while all the body beside has changed color, the inflamed retina no longer sees, the inflamed nose no longer smells, the inflamed mamma no longer yields milk, the inflamed finger has no more the proper sense of touch, and the inflamed cells that control nutrition no longer build up the tissues amid which they lie, but tend rather to a simple multiplication of their own cell forms, as do the cells of the early growing embryo. 7th. In an extensive inflammation the large arteries proceeding to the diseased part have their coats abnormally rigid, giving a harder beat to the pulse and determining a more abundant flow of blood than in the corresponding vessels of the healthy part. This doubtless results from the disorder of the vaso-motor (sympathetic) nerves, and this disorder is involved in the causation of the derangement of the capillary circulation as well, since the cutting across of a branch of these nerves going to a part promptly induces inflammatory changes in such part. This tendency to the production of inflammation through nervous influence is further shown in the extension to the other of a violent inflammation of one eye caused by a mechanical injury. Yet the essential changes may be induced in the tissues by irritants, though the nerves proceeding to the part have been cut or the blood-vessels tied.

It is worthy of notice that in extensive inflammations in otherwise healthy systems the circulating blood acquires a great increase of fibrinogen (often doubled), and the blood-globules become abnormally adhesive, so that before the drawn blood has time to coagulate the globules adhere together in masses and precipitate toward the bottom, leaving the upper layers of the clot of a dull yellow hue (buffy coat). This is shown in the blood of the healthy soliped, but in other animals it implies inflammation, apart from the conditions of plethora, anaemia, pregnancy, or over-driving. In

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the horse suffering from inflammation the normal buffy coat is increased. The blood of inflammation also coagulates more firmly and contracting most toward the centre assumes a cupped appearance on the surface.

These changes in the blood and nervous system are associated with an increase of body temperature and other manifestations of fever proportionate to the extent and violence of the inflammation. Again, in both inflammation and fever, the disease process may be of a strong type (sthenic), or of a low type (asthenic, adynamic).

INFLAMMATION IN NON-VASCULAR TISSUES.

Inflammation in tissues unprovided with blood-vessels may be observed in the irritated transparent cornea of the eye, or the cartilage covering the ends of bones in joints. Each when inflamed has its nutritive function impaired and loses its clear, translucent aspect, so much so that in the case of the eye one can no longer see into its interior. There may be as yet no real thickening, and no film of exudation formed on its surface. It is the pre-existing structures that have become opaque by change in the process of their nutrition. If a thin slice of this inflamed cartilage is treated with picric acid and placed under the microscope it is found that the nuclei within the cartilage-cells have become individually larger, that the cells embedded in the cartilaginous matrix are more numerous than is normal, and that, when the inflammation is most active, even cell-walls are no longer formed, but that a mass of rapidly multiplying nuclei is taking the place of the solid transparent matrix. As in the vascular tissue, so in the non-vascular, the power to build up the sound tissue (cartilage, corneal tissue) has been temporarily lost, while there is a mere growth of a cellular or embryonic tissue at the expense of the pre-existing structure. It remains to be added that in the inflamed cartilage or cornea there is an abundant infiltration of wandering

Inflammation and Fever.

white blood-cells, which have escaped from the vessels in the adjacent vascular tissue and made their way into the inflamed and softened cornea.

Thus in both types of inflammation, in the vascular and non-vascular tissues alike, there is this abundant concentration of plastic cells (white blood-cells and tissue nuclei), which assume for the time the functions of the cells of the early embryo from which all the varied tissues of the future animal are to be developed. Hence these cells, whicli grow so abundantly in inflamed parts with the size, form, and functions of embryonic cells, are not inaptly called embryonic cells, and the tissue, which they first form, embryonic tissue. These cells may be looked upon as the guardians of the system, charged with the duty of removing from the part all noxious, useless, or extraneous matter, and building up new tissue to repair the breach resulting from the injury. No sooner is the injury sustained than there is established an increased flow of blood through the vessels of the injured part (or through the nearest blood-vessels in case the injured structure has no vessels), the white globules are delayed in the capillary vessels and passed through their walls, and at the same time the tissue nuclei increase in size and numbers, abandon their habitual work of building up tissue, and together with the wandering blood-cells devote every power to the removal of the irritant and the repair of the breach. A similar work is effected in an entirely natural way in the tail of the tadpole when developing into a frog. Embryonic or lymphoid cells increase enormously in the tail, feeding upon the tissues of the now superfluous organ, and gradually absorbing and removing the whole mass. So it is, too, in the case of offensive living organisms introduced into a tissue. When bacteria have been thus inoculated inflammation is at once set up, and the accumulating cells, if numerous enough relatively to the micro-organism, take the bacteria into their substance and gradually dissolve and digest them, thereby rendering the inoculation harmless. If, however, the bacteria are too numerous or too poisonous (in themselves or their products) to be thus easily devoured, the opposite result ensues, the cells of the blood and tissues sent to dispute their invasion are themselves destroyed, and there takes place the death and removal of a circumscribed portion of tissue, an extensive suppuration and abscess, a spreading gangrene or ulcer, or a fatal general infection. A small dose of such bacteria is devoured, removed, and rendered harmless by the defensive work of these exudation-cells; a larger dose may establish a temporary stronghold in the tissues, which is finally circumscribed, loosened, and thrown off as a slough by the active agency of the investing animal cells around it, while a still larger dose conquers the defending army, and extends its sway over the entire body with grave or fatal effect.

INFLAMMATORY EXUDATIONS AND EFFUSIONS.

These vary much in different cases according to the grade and stage of the inflammation, the part affected, and the subject of the disease.

1st. Serous Exudations. These consist of the liquid elements of the blood, with only a limited amount of the fibrine-forming element (fibrinogen), and consequently little tendency to clot firmly. The effused fluid is distinguished from the liquid of mechanical dropsy by the presence in it of the fibrinogen, of albumen, of cells, and of nuclei. The dropsical fluid does not coagulate unless heated, and contains less common salt and phosphates than the inflammatory effusion. Serous exudations are characteristic of the early stages of inflammation, and of inflammations of serous membranes (pleura, peritoneum, joints) in strong, vigorous subjects. They are especially dangerous by reason of interference with the functions of organs by pressure, as with

Inflammation and Fever.

the dilatation of the lungs, the movements of the heart, the movement of joints, or the integrity of the brain or spinal cord. When the disease that caused them has subsided they are usually speedily reabsorbed, though not invariably so.

2d. Mucous exudations are formed wherever mucus is produced in health, as in catarrhs of nose, eyes, throat, and other mucous membranes. They contain filaments of precipitated mucin insoluble in acetic acid or alcohol, and globular cells in all stages of change from the mucous to the pus-corpuscle, the latter recognized by its bipartite or tripartite nucleus, manifested by contact with acetic acid.

3d. Fibrinous Exudations. Inflammatory lymph. This oozes out through the vessels in a liquid state and afterward coagulates by reason of its contained fibrinogen or plasmin, which exists ready formed, but in solution, in the blood. It is the excess of plasmin which distinguishes this from the serous exudation. The coagulation of plasmin may result from the ferment globulin escaped from the blood-globules, and it always coagulates promptly on contact with inflamed tissues, probably from the presence of the same or an allied ferment. If, on the other hand, the exudation escapes into a healthy cavity, and comes in contact with healthy tissues only, it may, like blood in similar circumstances, remain liquid for months. It is specially injurious by enveloping organs (lungs, heart, bowels, iris) and hampering their movements, or by binding them to adjacent structures by false membranes. In coagulating it becomes first fibrillar, then granular, and finally undergoes molecular disintegration (Cornil and Ranvier) or development into new tissue (Paget). When organized it usually takes the form of the adjacent tissue; in granulating wounds and between serous membranes it is fibrous, and between the broken ends of bones it is bon} 7 .

Fibrinous exudations are especially seen in a high grade of inflammation, in connection with fibrous tissues and in strong vigorous subjects.

4th. Blood Exudations. As already stated, blood-globules escape through the walls of the vessels in all inflammations, though seldom in such quantity as even to stain the tissues. Minute ruptures of the capillary vessels are not uncommon with punctiform clots in the tissues, but extensive escapes of blood are usually indicative of a specially unhealthy type of inflammation, usually associated with a specific and deadly poison, as in anthrax, rinderpest, swine-plague, purpura hemorrhagica. They are further most common from newly formed vessels, which are yet soft and possessed of little power of resistance.

5th. Croupous Exudations. These are deposited on diseased surfaces in the form of false membranes, composed mainly of cell-elements, epithelium, and pus-corpuscles in a thin network of fibrine, mucin, or both. To these belong the membranous products of croup and diphtheria, and the false membranes that appear independently of these poisons on violently inflamed mucous membranes (croupous enteritis, etc.)

RESULTS OF INFLAMMATION.

Resolution. This is the condition in which a slight inflammation, which has not advanced beyond the stage of liquid effusion, has the exudate reabsorbed, and the blood-vessels and tissues restored to their healthy condition. If this occurs with extraordinary rapidity the term delitescence is applied to it, and there is danger of its reappearance elsewhere by reason of clots from the capillaries being suddenly loosened and washed onward to block other capillaries in the lungs or other distant organs. This occurrence of a secondary disease at a distance, when a first has suddenly subsided, has been named metastasis, and is usually due to the blocking of the capillaries by blood-clots.

Inflammation and Fever.

Inflammatory New Formations. Of the growths in lymph there are two principal kinds : first, the plastic, fibrinous, granular, or molecular y and second, the aplastic, croupous, or corpuscular. The first form tends to develop into new structure, the second to disintegrate and decay. The tendency to one or other form depends largely on the strength or weakness of the system's health, on the deficiency or excess of corpuscles in the exuded fluid, and on the distance of the latter from living tissues and blood- supply. Much also depends on the predisposition of the genns, the tendency to suppuration in lymph being in a descending series from horse, ass, and mule, through ox and sheep, to dog, pig, and, finally, the bird, in which latter suppuration is quite exceptional.

Suppuration. In inflammations of a high type, in those occurring on the skin or mucous membranes in which there is an extraordinary increase of nuclei and embryonal cells, and in lymph thrown out in excess at one point, so that its central parts are far from vascular tissue, the cell elements undergo a rapid increase and degradation into pus-corpuscles, and its solidified intercellular lymph undergoes granular decay and liquefaction into the liquid of pus.

While the above conditions are favorable to the formation of pus, the process of suppuration must now be recognized as an infective process due to the propagation of bacteria (mainly chain forms — Streptococcus pyogenes— and cluster-groups — Staphylococcus pyogenes). These or other bacteria are found in the pus of acute abscesses, and when absent in chronic abscesses are to be considered as having perished since the abscess was recent and active. Inoculation of a rabbit with an excess of the pus of an acute abscess produces general purulent infection (pyaemia) and early death; from a medium dose an abscess is produced; while from a small dose there is no effect whatever. In the latter case the bacteria are overcome and devoured by the abundauce of vitally potent white blood-globules and tissue-cells. This pus-forming action of these bacteria explains the great difference in results in wounds exposed to the air and those iti the interior of the body and far removed from air and its floating bacteria. A broken bone, with no wound in the skin and little injury to parts around the fracture, is readily repaired, without any formation of pus, if merely kept still and immovable ; whereas a broken bone, continuous with a wound through the skin, always tends to form pus and is extremely dangerous even to life. The tendency of every open sore is to form pus on its surface, but this may be arrested and prevented by a free use of disinfectants and a covering which shall arrest and filter out the germs.

Similarly in an abscess the injection of disinfectants, without the formation of any perceptible permanent opening to the outer air, will put a stop to the pus-formation. The subjection of an inflamed part to the control of these pus-forming bacteria is dependent on the lowered vitality and power of resistance of the inflamed tissues, and of the white cells of their circulating blood. Healthy parts can successfully resist them, though they are constantly present in surrounding air and on objects, but in this, as in all other cases ; of bacterial infection, so soon as the tissue is injured, inflamed, and lowered in its power of vital resistance, the pyogenic bacteria assail it successfully. Hence, too, the more abundant exudations of lymph, the centres of which are farthest removed from the healthy tissues, and from the influence of their vital resistance, are the most prone to suppuration. That the germs can make their way to such deep-seated exudations in the substance of solid tissues is to be accounted for by their gradual advance through the inflamed and weakened structures from the adjacent skin or mucous membrane, or in some instances by reason of their presence in small numbers in the blood. It is further noteworthy that those animals in which suppuration does not occur readily are such as have a special power of resistance to some other organic poisons. Thus the hog, which is supposed to be proof against snakebite, is also, to a large extent, proof against the pus-forming bacteria. For further notice of this subject see article on Pyazmia.

Pus. This is a white, or yellowish-white, creamy-looking product, composed of a clear, transparent fluid, rendered opaque by numerous floating pus-corpuscles. These pus-corpuscles have the same size as the white globules of the blood (^Vrr to -3 oVir inch) and are peculiar in that each shows within it three or more nuclei, which become visible on the addition of a drop of water or acetic acid. Each of the common embryonal cells found in the inflamed tissue contains two nuclei, the indication of the active increase by division into two, but when the supply of nutriment is checked the nuclei continue to divide, while the cells remain unchanged, and thus every cell comes to contain several nuclei in addition to fatty granules, and constitute pus-corpuscles.

When pus is formed in a well-maintained system and tissue, the outer layer of the lymph is developed into a fibrous sac inclosing the liquid pus and constituting an abscess. In an unhealthy system, or when the inflammation depends on some injurious poison, like that of erysipelas, this sac may not be formed, and the pus, burrowing into and between different organs, destroys the connections and substance — diffuse suppuration. When an abscess has formed in soft tissues its investing sac shrinks as it assumes the fibrous character, and the confined pus being incapable of compression, presses the membrane outward on the side in which the surrounding tissues are most loose and least resistant, hence, usually, though not always, in the direction of the skin, the soft tissues become absorbed and removed in the track of the advancing pus ; and, finally, the latter reaches a surface and escapes. Thus, an abscess usually bursts through the skin, but also, at times, through a mucous membrane into the lungs, bowels, etc., or through a serous membrane into chest, abdomen, etc. When an abscess is formed in bone or dense fibrous tissues which press equally on all sides, it may remain imprisoned for months and j'ears after all inflammation has subsided, constituting an indolent or cold abscess. When the imprisoned pus is inclosed by thick fibrous or resistant tissues at all points but one, it will make its way along the narrow passage of yielding tissue, but as the resulting outlet is constricted, long, and tortuous, the contents cannot readily escape through it nor the walls of the abscess contract so as to expel the confined pus, and the latter goes on forming and discharging through the narrow outlet for months or years. This is & fistula or sinus.

Healing by Adhesion or First Intention. When a cleancut wound has the blood staunched and its lips brought together without exposure to the air (or contact with pyogenic germs), they adhere at once and heal without pus or any appreciable formation of new tissue. Here the lymph thrown out on the cut surfaces agglutinates them, and the cells, multiplying, form a thin layer of embryonic tissue which gradually develops into a fibrous structure and repairs the breach without any perceptible scar.

Healing by Second Intention. Granulation. When a wound has caused destruction of tissue, or when a simple incision is left exposed to the air, the breach is filled up by new tissue through the process known as granulation. The superficial layer of lymph thrown out on the raw surface becomes oxidized and degenerates into pus, while the deeper layers become solid, fibrillated, the seat of cell-growth, and are finally transformed into a fibrous structure. New blood-vessels form in loops in the developing lymph and constitute the bright-red granulation-points which cover the raw surface. The fibrous tissue into which the lymph is transformed undergoes gradual contraction in development, and thus, day by day, the edges of the adjacent healthy skin are drawn in, so as to cover the wound more or less perfectly, and a slight scar only is left when healing has been accomplished.

Granule Corpuscles and Masses. This is another degenerative transformation in lymph and, is seen mainly in inflamed glands and brain- and lung-tissue. The cells found in the exuded lymph are made up of granules ytdto mcn m diameter, and besides these, large, irregularly shaped masses of granules are extended along the capillary blood-vessels. After the lymph has coagulated these granular masses soften and liquefy preliminary to re-absorption and removal, and the restoration of the tissue to a healthy condition. When in excess this softens and disintegrates the tissues, leading to permanent loss of substance.

Development of Lymph into Tissue. This is equivalent to what takes place in the formation of the sac of the abscess or of granulation-tissue. The liquid lymph in coagulating, becomes fibrillar, and the exuded cells and nuclei and those of the adjacent tissue, having an abundant supply of blood and nutriment, multiply first as simple, rounded embryonic cells, then deposit around them new tissue, becoming elongated, spindle-shaped, branching, etc., and thus get imbedded in a fibrous material of their own formation. These new formations are usually of a low tj^pe of organization, like white fibrous tissue or bone, and hence, although breaches in the higher structures like muscle, nerve, gland, skin, are filled up, it is usually only by the drawing together of the remaining healthy parts by these new formations without the restoration of any of the original tissue which has been destroyed. The cicatrix (scar), alone is made up of new material.

Lymph developing in this way may undergo any degeneration to which normal tissues are subject. Thus it may undergo black pigmentary {melanotic) degeneration, it may become impregnated with lime- salts {calcified), it may wither up into a hard gelatiniform or horny mass, or it may xmdiQYgo fatty degeneration.

Fatty degeneration is the most common form, and consists in the excessive deposit of fatty granules, first in the cells which are in excess or badly nourished, and next in the adjacent tissue, the normal elements of which are replaced by fatty granules.

Softening is an almost constant result of inflammation. The exudate infiltrates and separates the tissue elements, destroying their cohesion ; its liquefaction impairs this still further, and the more or less perfect transformation of the tissue into embryonic tissue entails the loss of its rigidity and power of resistance. Thus the inflamed brain-tissue may become a mere pulp, and the inflamed bone may be cut with a knife.