Special Report on Diseases of Cattle Part 6

Fig. 2. Simple probang, used to dislodge foreign bodies, like apples, potatoes, eggs, etc., which have become fastened or stuck in the esophagus or gullet.

Fig. 3. Grasping or forceps probang. This instrument, also intended to remove obstructions from the gullet, has a spring forceps at one end in the place of the cup-like arrangement at the end of the simple probang. The forceps are closed while the probang is being introduced; their blades are regulated by a screw in the handle of the instrument. This probang is used to grasp and withdraw an article which may have lodged in the gullet and can not be forced into the stomach by use of the simple probang.

Fig. 4. Wooden gag, used when the probang is to be pa.s.sed. The gag is a piece of wood which fits in the animal's mouth; a cord pa.s.ses over the head to hold it in place. The central opening in the wood is intended for the pa.s.sage of the probang.

Figs. 5_a_ and 5_b._ Trocar and cannula; 5_a_ shows the trocar covered by the cannula; 5_b_, the cannula from which the trocar has been withdrawn.

This instrument is used when the rumen or first stomach becomes distended with gas. The trocar covered by the cannula is forced into the rumen, the trocar withdrawn, and the cannula allowed to remain until the gas has escaped.

Fig. 6. Section at right angles through the abdominal wall, showing a hernia or rupture. (Taken from D'Arboval. Dictionnaire de Medecine, de Chirurgie de Hygiene): _a a_, The abdominal muscles cut across; _v_, opening in the abdominal wall permitting the intestines _i i_ to pa.s.s through and outward between the abdominal wall and the skin; _p p_, peritoneum, or membrane lining the abdominal cavity, carried through the opening _o_ by the loop of intestine and forming the sac S, the outer walls of which are marked _b f b._

PLATE IV. Microscopic anatomy of the liver. The liver is composed of innumerable small lobules, from 1/20 to 1/10 inch in diameter. The lobules are held together by a small amount of fibrous tissue, in which the bile ducts and larger blood vessels are lodged.

Fig. 1 Ill.u.s.trates the structure of a lobule; _v v_, interlobular veins or the veins between the lobules. These are branches of the portal vein, which carries blood from the stomach and intestines to the liver; _c c_, capillaries, or very fine blood vessels, extending as a very fine network between the groups of liver cells from the interlobular vein to the center of the lobule and emptying there into the intralobular vein to the center of the lobule; _v c_, intralobular vein, or the vein within the lobule.

This vessel pa.s.ses out of the lobule and there becomes the sublobular vein; _v s_, sublobular vein. This joins other similar veins and helps to form the hepatic vein, through which the blood leaves the liver; _d d_, the position of the liver cells between the meshes of the capillaries; _A A_, branches of the hepatic artery to the interlobular connective tissue and the walls of the large veins and large bile ducts. These branches are seen at _r r_ and form the vena vascularis; _v v_, vena vascularis; _i i_, branches of the hepatic artery entering the substance of the lobule and connecting with capillaries from the interlobular vein. The use of the hepatic artery is to nourish the liver, while the other vessels carry blood to be modified by the liver cells in certain important directions; _g_, branches of the bile ducts, carrying bile from the various lobules into the gall bladder and into the intestines; _x x_, intralobular bile capillaries between the liver cells. These form a network of very minute tubes surrounding each ultimate cell, which receives the bile as it is formed by the liver cells and carried outward as described.

Fig. 2. Isolated liver cells: _c_, blood capillary; _a_, fine bile capillary channel.

PLATE V. Ergot in hay: 1, bluegra.s.s; 2, timothy; 3, wild rye; 4, redtop.

Ergot is a fungus which may affect any member of the gra.s.s family. The spore of the fungus, by some means brought in contact with the undeveloped seed of the gra.s.s, grows, obliterates the seed, and practically takes its place. When hay affected with ergot is fed to animals it is productive of a characteristic and serious affection or poisoning known as ergotism.

PLATE VI. Ergotism, or the effects of ergot. The lower part of the limb of a cow, showing the loss of skin and flesh in a narrow ring around the pastern bone and the exposure of the bone itself.

POISONS AND POISONING.

By V. T. ATKINSON, V. S.

[Revised by C. DWIGHT MARSH, Ph. D.]

DEFINITION OF A POISON.

To define clearly the meaning of the word "poison" is somewhat difficult.

Even in law the word has never been defined, and when a definition is attempted we are apt to include either too much or too little. The following definition given by Husemann is perhaps the best: "Poisons are those substances, inorganic or organic, existing in the organism or introduced from the outside, produced artificially or formed as natural products, which, through their chemical nature, under definite conditions, so affect some organ of a living organism that the health or well-being of the organism is temporarily or chronically injured." The common conception of a poison is any substance which, in small quant.i.ty, will destroy life, except such as act by purely mechanical means, as, for example, powdered gla.s.s.

Some substances that are not usually looked upon as poisons may destroy life if given in large doses, such as common salt. Other substances which are perfectly harmless when taken into the body in the usual way are poisons if injected into the circulation, such as distilled water, milk, or glycerin. Living organisms are not "chemical substances," and are not considered in this connection.

SOURCES OF POISONING.

Poisoning may come from many causes, among the chief of which are the following:

(1) _Errors in medication._--By using the wrong substance or too large dose an animal may be poisoned.

(2) _The exposure of poisons used for horticultural, technical, or other legitimate purposes._--Poisons used for spraying plants, disinfecting, poisoning vermin, dipping cattle or sheep, painting, smelting, dyeing, or other purposes may be so handled as to come within the reach of animals.

(3) _Damaged food._--Food that has undergone putrefaction or certain kinds of fermentation or heating, may have become poisonous, producing forage poisoning, meat poisoning, cheese poisoning, etc.

(4) _Poisonous plants in the pasture or forage._

(5) _The bite or sting of a poisonous insect or the bite of an animal._

(6) _Malicious poisoning._

THE ACTION OF POISONS.

The action of poisons may be either local, and exerted directly on the tissues with which they come in contact, or remote, acting through the circulation or the nervous system; or both local and remote action may be exerted by the same drug. Poisons which act locally generally either destroy by corrosion the tissues with which they come in contact or by inhalation set up acute inflammation. When any corrosive agent is taken into the stomach in poisonous quant.i.ties, a group of symptoms is developed which is common to all. The tissues with which the agent comes in contact are destroyed, sloughing and acute inflammation of the surrounding structures take place; intense pain in the abdomen and death ensue. In a like manner, but with less rapidity, the same result is reached if the agent used be not of a sufficiently corrosive nature to destroy the tissues, but sufficiently irritating to set up acute inflammation of the mucous membrane of the digestive tract. If the poison exerts a remote influence alone, the action is quite different, little or no local effect being produced upon the digestive organs.

To produce an effect on some part of the body distant from the channel of entrance, a poison must have been absorbed and carried in the blood to the central nervous system or other region involved. The poisonous effect of any substance is modified by the quant.i.ty used; by its chemical combinations; by the part of the animal structure with which it comes in contact; by the physical condition of the subject; and also by the rapidity with which the poison is excreted. As an ill.u.s.tration, opium may be given with safety in much larger doses to an animal suffering from acute pain than to one free from pain, and to an adult animal with greater safety than to a young one. The rapidity with which the poison is absorbed, owing to the part of the body with which it is brought in contact, is also an important factor. So marked is this quality that some agents which have the power of destroying life with almost absolute certainty when introduced beneath the skin, may be taken into the stomach without causing inconvenience, as curara, the arrow poisons, or the venomous secretion of snakes. Other agents in chemical combination may tend to intensify, lessen, or wholly neutralize the poisonous effect. For example, a.r.s.enic in itself has well-marked poisonous properties, but when brought in contact with dialyzed iron it forms an insoluble compound and becomes innocuous.

Idiosyncrasies are not so noticeable in cattle practice as in practice among human beings, but the uncertainty with which some drugs exert their influence would lead us to believe that well-marked differences in susceptibility exist. Even in some cases a tolerance for poison is engendered, so that in a herd of animals equally exposed injurious or fatal effects do not appear with uniformity. For example, among cattle that are compelled to drink water holding in solution a salt of lead the effects of the poisoning will be found varying all the way from fatality to imperceptibility.

GENERAL SYMPTOMS OF POISONING.

It is not always easy to differentiate between poisoning and some disease.

Indeed, examination during the life of the animal is sometimes wholly inadequate to the formation of an opinion as to whether the case is one of poisoning or, if it is, as to what the poison may be. A chemical and physical examination after the death of the animal may be necessary to clear up the doubt. On the other hand, the symptoms may be of such a nature as to point unmistakably to poisoning with a certain agent. In general, the following cla.s.ses of symptoms may be regarded as indicative of poisoning: Sudden onset of the disease without visible cause, a number of animals being similarly affected at once, with severe gastrointestinal disorder or derangement of the nervous system, or both; sudden alteration of heart action in relation to frequency, force, or rhythm; local irritation, dyspnea, or change in the urine or urination.

After death, lesions of the greatest variety may be found, and it is necessary for one to be skilled in anatomy and pathology in order to determine their significance. Oftentimes the stomach and intestines are red, have thick walls, and contain blood. This signifies a severe irritant, such as a.r.s.enic or corrosive sublimate. Other alterations sometimes found are inflammation of the kidneys or bladder, points of hemorrhage in various organs, changes in the blood, congestion of the lungs, and certain microscopic changes.

GENERAL TREATMENT.

The treatment of animals suffering from poison must vary according to the nature of the toxic agent. There are a few general plans of action, however, which should be followed so far as possible. In man and in some of the smaller animals it is possible to eliminate unabsorbed poison by the use of the stomach pump or by causing vomiting. These proceedings are impracticable in cattle. It is well, therefore, in many cases to endeavor to expel the unabsorbed poison by emptying the digestive tract, so far as may be, with a nonirritating purge. Castor oil in doses of 1 pint to 2 quarts is adapted to this purpose. If the poison is known to be nonirritant--as a narcotic plant--from 10 to 20 drops of croton oil may be given with a quart of castor oil. When poisons are somewhat prolonged in their effect, Epsom salt in doses of 1 pound can be given advantageously.

To protect the mucous membrane from the action of strong irritants, one may give flaxseed tea, barley water, the whites of eggs, milk, b.u.t.ter, olive oil, or fresh lard. Chemical antidotes may sometimes be used for special poisons, as advised below. In general, if an acid has been taken it may be neutralized with an alkali, such as chalk, magnesia, bicarbonate of soda (baking soda), ammonia (diluted), or soap. If the poison is an alkali, such as caustic soda or potash (lye), or ammonia, an acid, such as diluted (1 per cent) sulphuric acid or vinegar, may be administered. Special treatments and antidotes are considered below.

A poisonous agent may be so gradually introduced into the system as to slowly develop the power of resistance against its own action. In other cases where the poison is introduced slowly the poisonous action becomes acc.u.mulative, and, although there is no increase in the quant.i.ty taken, violent symptoms are suddenly developed, as if the whole amount, the consumption of which may have extended over a considerable period, had been given in one dose. Other agents, poisonous in their nature, tend to deteriorate some of the important organs, and, interfering with their natural functions, are productive of conditions of ill health which, although not necessarily fatal, are important. Such might properly be called chronic poisons. Poisons of themselves dangerous when administered in large doses are used medicinally for curative purposes, and a very large percentage of the pharmaceutical preparations used in the practice of medicine if given in excessive quant.i.ties may produce serious results. In the administration of medicines, therefore, care should be exercised not only that the animal is not poisoned by the administration of an excessive dose but that injury is not done by continued treatment with medicines the administration of which is not called for.

MINERAL POISONS.

a.r.s.eNIC POISONING.

Of the common irritant and corrosive poisons, a.r.s.enic, especially one of its compounds (Paris green), is likely to be the most dangerous to our cla.s.s of patients. The common practice of using Paris green and other compounds of a.r.s.enic as insecticides for the destruction of potato beetle and other insect enemies of the farmer and fruit grower has had the effect of introducing it into almost all farming establishments. White a.r.s.enic is also a princ.i.p.al ingredient in some popular dipping preparations, and poisoning from this source occasionally takes place when, after dipping, animals are allowed to run in a yard in which there is loose fodder. The drippings from the animals falling on the fodder render it poisonous and dangerous to animal life if eaten. Familiarity with its use has in many instances tended to breed contempt for its potency as a poison. Rat poisons often contain a.r.s.enic. The excessive use of a.r.s.enic as a tonic, or of "condition powders" containing a.r.s.enic, has been the means of poisoning many animals. This is the common poison used by malicious persons with criminal intent. The poison may also be absorbed through wounds or through the skin if used as a dip or bath.

If a large dose is given, at once acute poisoning is produced; if repeated small doses are given, chronic poisoning may result. The poisonous dose for an ox is from 3 drams to 1 ounce.

_Symptoms._--The symptoms of acute poisoning first appear as those of colic; the animal is restless, stamping with the feet, lying down and getting up. There is tenderness on pressure over the abdomen. The acute symptoms increase; in a few hours violent diarrhea is developed; in many cases blood and shreds of detached mucous membrane are mixed with the evacuations. There is irregular and feeble pulse and respiration, and death is likely to supervene between the eighteenth hour and the third day. If the latter period is pa.s.sed, there is a reasonable hope of recovery.

In chronic poisoning the symptoms are similar to those of chronic gastrointestinal catarrh, with indigestion, diarrhea, and general weakness and loss of condition.

_Treatment._--The antidote for a.r.s.enic is a solution of hydrated oxid of iron in water. It should be prepared fresh by mixing a solution of sulphate of iron, made by dissolving 4 ounces of sulphate of iron in one-half pint water, with a suspension of 1 ounce of magnesia in one-half pint water.

This quant.i.ty is sufficient for one dose for a cow and may be repeated in an hour, if much a.r.s.enic was taken. A solution of calcined magnesia or powdered iron or iron filings or iron scale from a blacksmith's forge may be given in the absence of other remedies. Powdered sulphur is of some value as an antidote. One must also administer protectives, such as linseed tea, barley water, whites of eggs, etc.