These are formed generally by the extremities of the long bones

These are formed generally by the extremities of the long bones

These are formed generally by the extremities of the long bones

We have referred to that special formation of the external surface of a bone by which it is adapted to form a joint or articulation, either movable or fixed, and a concise examination of the formation and structure of the movable articulations will here be in place. These are formed generally by the extremities of the long bones, or may exist on the surfaces of the short ones. The points or regions where the contact occurs are denominated the articular surface, which assumes from this circumstance a considerable variety of aspect and form, being in one case comparatively flat and another elevated; or as forming a protruding head or knob, with a distinct convexity; and again presenting a corresponding depression or cavity, accurately adapted to complete, by their coaptation, the ball-and-socket joint. The articulation of the arm and shoulder is an example of the first kind, while that of the hip with the thigh bone is a perfect exhibition of the latter.

At the upper part of the bone of the arm

At the upper part of the bone of the arm

At the upper part of the bone of the arm

Illustrations in point of the agency of the synovial fluid in assisting the sliding movements of the tendons may be found under their various forms at the shoulder joint, at the upper part of the bone of the arm, at the posterior part of the knee joint, and also at the fetlocks, on their posterior part.

As the tendons, whether singly or in company with others, pass over these natural pulleys they are retained in place by strong, fibrous bands or sheaths, which are by no means exempt from danger of injury, as will be readily inferred from a consideration of their important special use as supports and reenforcements of the tendons themselves, with which they must necessarily share the stress of whatever force or strain is brought to bear upon both or either.

The active organs of locomotion

The active organs of locomotion

The active organs of locomotion

The active organs of locomotion, the muscles (see Plate XXIII), speaking generally, form the fleshy covering of the external part of the skeleton and surround the bones of the extremities. They vary greatly in shape and size, being flat, triangular, long, short, or broad, and are variously and capriciously named, some from their shape, some from their situation, others from their use; and thus we have abductors and adductors the pyramidal, orbicular, the digastricus, the vastus, and so on. Those which are under the control of the will, known as the voluntary muscles, appear in the form of fleshy structures, red in color, and with fibers of various degrees of fineness, and are composed of fasciculi, or bundles of fibers, united by connective or cellular tissue, each fasciculus being composed of smaller ones but united in a similar manner to compose the larger formations, each of which is enveloped by a structure of similar nature known as the sarcolemma. Many of the muscles are united to the bones by the direct contact of their fleshy fibers, but in other instances the body of the muscle is more or less gradually transformed into a cordy or membranous structure known as the tendon or sinew, and the attachment is made by the very short fibrous threads through the medium of a long tendinous band, which, passing from a single one to several others of the bones, effects its object at a point far distant from its original attachment. In thus carrying its action from one bone to another, or from one region of a limb to another, these tendons must necessarily have smooth surfaces over which to glide, either upon the bones themselves or formed at their articulations, and this need is supplied by the secretion of the synovial fluid, a yellowish, unctuous substance, furnished by a peculiar tendinous synovial sac designed for the purpose.

The secreting membrane of the bony structure

The secreting membrane of the bony structure

The secreting membrane of the bony structure

The substance of the bone is composed of a mass of combined earthy and animal matter surrounded by a fine, fibrous enveloping membrane (the periosteum) which is intimately adherent to the external surface of the bone, and is, in fact, the secreting membrane of the bony structure. The bony tissue proper is of two consistencies, the external portion being hard and "compact," and called by the latter term, while the internal, known as the "spongy" or "areolar tissue," corresponds to the descriptive terms. Those of the bones that possess this latter consistency contain also, in their spongy portion, the medullary substance known as marrow, which is deposited in large quantities in the interior of the long bones, and especially where a central cavity exists, called, for that reason, the medullary cavity. The nourishment of the bones is effected by means of what is known as the nutrient foramen, an opening established for the passage of the blood vessels which convey the nourishment necessary to the interior of the organ. Concerning the nourishment of the skeleton, there are other minutiae, such as the venous arrangement and the classification of their arterial vessels into several orders, which, though of interest as an abstract study, are not of sufficient practical value to refer to here.

Anatomy.

Anatomy.

The bones, then, are the hard organs which in their connection and totality constitute the skeleton of an animal (see Plate XXIII). They are of various forms, three of which the long, the flat, and the small are recognized in the extremities. These are more or less regular in their form, but present upon their surfaces a variety of aspects, exhibiting in turn, according to the requirement of each case, a roughened or smooth surface, variously marked with grooves, crests, eminences, and depressions, for the necessary muscular attachments, and, as before mentioned, are connected by articulations and joints, of which some are immovable and others movable.

A concise examination of the general anatomy of these organs

A concise examination of the general anatomy of these organs

A concise examination of the general anatomy of these organs

A concise examination of the general anatomy of these organs, however, must precede the consideration of the pathological questions pertaining to the subject. A statement, such as we have just given, containing only the briefest hint of matters which, though not necessarily in their ultimate scientific minutiae, must be clearly comprehended in order to acquire a symmetrical and satisfactory view of the theme as a practical collation of facts to be remembered, analyzed, applied, and utilized.

It was the great Bacon who wrote: "The human body may be compared, from its complex and delicate organization, to a musical instrument of the most perfect construction, but exceedingly liable to derangement." In its degree the remark is equally applicable to the equine body, and if we would keep it in tune and profit by its harmonious action we must at least acquaint ourselves with the relations of its parts and the mode of their cooperation.

These points of attachment appear sometimes as an eminence

These points of attachment appear sometimes as an eminence

These points of attachment appear sometimes as an eminence

The function of locomotion is performed by the action of two principal systems of organs, known in anatomical and physiological terminology as passive and active, the muscles performing the active and the bones the passive portion of the movement. The necessary connection between the cooperating parts of the organism is effected by means of a vital contact by which the muscle is attached to the bone at certain determinate points on the surface of the latter. These points of attachment appear sometimes as an eminence, sometimes as a depression, sometimes a border or an angle, or again as a mere roughness, but each perfectly fulfilling its purpose, while the necessary motion is provided for by the formation of the ends of the long bones into the requisite articulations, joints, or hinges. Every motion is the product of the contraction of one or more of the muscles, which, as it acts upon the bony levers, gives rise to a movement of extension or flexion, abduction or adduction, rotation or circumduction. The movement of abduction is that which passes from and that of adduction that which passes toward the median line, or the center of the body. The movements of flexion and extension are too well understood to need defining. It is the combination and rapid alterations of these movements which produce the different postures and various gaits of the animal, and it is their interruption and derangement, from whatever causes, which constitute the pathological condition known as lameness.

And treating in detail of the causes

And treating in detail of the causes

And treating in detail of the causes

The horse is too important a factor in the practical details of human life and fills too large a place in the business and pleasure of the world to justify any indifference to his needs and physical comfort or neglect in respect to the preservation of his peculiar powers for usefulness. In entering somewhat largely, therefore, upon a review of the subject, and treating in detail of the causes, the symptoms, the progress, the treatment, the results, and the consequences of lameness in the horse, we are performing a duty which needs no word of apology or justification. The subject explains and justifies itself, and is its own vindication and illustration, if any are needed.

Of all the animal tribe the horse

Of all the animal tribe the horse

Of all the animal tribe the horse

Of all the animal tribe the horse, in a state of domesticity, is the largest sharer with his master in his liability to the accidents and dangers which are among the incidents of civilized life. From his exposure to the missiles of war on the battlefield to his chance of picking up a nail from the city pavement there is no hour when he is not in danger of incurring injuries which for their repair may demand the best skill of the veterinary practitioner. This is true not alone of casualties which belong to the class of external and traumatic cases, but includes as well those of a kind perhaps more numerous, which may result in lesions of internal parts, frequently the most serious and obscure of all in their nature and effects.

Formerly Principal of The American Veterinary College, New York. (Revised by John r. Mohler, a. M., v. m. D.)

Formerly Principal of The American Veterinary College, New York. (Revised by John r. Mohler, a. M., v. m. D.)

It is as living, organized, locomotive machines that the horse, camel, ox, and their burden-bearing companions are of practical value to man. Hence the consideration of their usefulness and consequent value to their human masters ultimately and naturally resolves itself into an inquiry concerning the condition of that special portion of their organism which controls their function of locomotion. This is especially true in regard to the members of the equine family, the most numerous and valuable of all the beasts of burden, and it naturally follows that with the horse for a subject of discussion the special topic and leading theme of inquiry, by an easy lapse, will become an inquest into the condition and efficiency of his power for usefulness as a carrier or traveler. There is a great deal of abstract interest in the study of that endowment of the animal economy which enables its possessor to change his place at will and convey himself whithersoever his needs or his moods may incline him; how much greater, however, the interest that attaches to the subject when it becomes a practical and economic question and includes within its purview the various related topics which belong to the domains of physiology, pathology, therapeutics, and the entire round of scientific investigation into which it is finally merged as a subject for medical and surgical consideration in a word, of actual disease and its treatment. It is not surprising that the intricate and complicated apparatus of locomotion, with its symmetry and harmony of movement and the perfection and beauty of its details and adjuncts, by students of creative design and attentive observers or nature and her marvelous contrivances and adaptations, should be admiringly denominated a living machine.

And it is frequently exhibited as a snake in the eye

And it is frequently exhibited as a snake in the eye

And it is frequently exhibited as a snake in the eye

Setaria equina is a delicate, white, silvery-looking worm, which I have repeatedly found 2 inches in length (a length as great as 5 inches has been reported). It invades the aqueous humor, where its constant active movements make it an object of great interest, and it is frequently exhibited as a "snake in the eye." When present in the eye it causes inflammation and has to be removed through an incision made with the lancet in the upper border of the cornea close to the sclerotic, the point of the instrument being directed slightly forward to avoid injury to the iris. Then cold water or astringent antiseptic lotions should be applied.

Filaria conjunctivae, resembling Setaria equina very much in size and general appearance, is another roundworm which has been found in the eye of the horse.

The echinococcus, the cystic or larval stage of the echinococcus tapeworm of the dog, has been found in the eye of the horse, and a cysticercus is also reported.

This worm is normally a parasite of the peritoneal cavity, and is probably transmitted from one horse to another by some biting insect which becomes infected by embryos in the blood. M. C. Hall.

Parasites in The Eye.

Parasites in The Eye.

Acari in the eye have been incidentally alluded to under inflammation of the lids.

Filaria palpebralis is a white worm, one-half to 1 inch long, which inhabits the lacrimal duct and the underside of the eyelids and haw in the horse, producing a verminous conjunctivitis. The first step in treatment in such cases is to remove the worm with forceps, then treat as for external inflammation.

Staphyloma.

Staphyloma.

This consists in a bulging forward of the cornea at a given point by the sacculate yielding and distention of its coats, and it may be either transparent or opaque and vascular. In the last form the iris has become adherent to the back of the cornea, and the whole structure is filled with blood vessels. In the first form the bulging cornea is attenuated; in the last it may be thickened. The best treatment is by excision of a portion of the rise so as to relieve the intraocular pressure.

Tumors of The Eyeball.

Tumors of The Eyeball.

A variety of tumors attack the eyeball dermoid, papillary, fatty, cystic, and melanotic but perhaps the most frequent in the horse is encephaloid cancer. This may grow in or on the globe, the haw, the eyelid, or the bones of the orbit, and can be remedied, if at all, only by early and thorough excision. It may be distinguished from the less dangerous tumors by its softness, friability, and great vascularity, bleeding on the slightest touch, as well as by its anatomical structure.

The symptoms are wide dilatation of the pupils

The symptoms are wide dilatation of the pupils

The symptoms are wide dilatation of the pupils

Symptoms. The symptoms are wide dilatation of the pupils, so as to expose fully the interior of the globe, the expansion remaining the same in light and darkness. Ordinary eyes when brought to the light have the pupils suddenly contract and then dilate and contract alternately until they adapt themselves to the light. The horse does not swerve when a feint to strike is made unless the hand causes a current of air. The ears are held erect, turn quickly toward any noise, and the horse steps high to avoid stumbling over objects which it can not see.

Treatment is only useful when the disease is symptomatic of some removable cause, like congested brain, overloaded stomach, or gravid womb. When recovery does not follow the termination of these conditions, apply a blister behind the ear and give one-half dram doses of nux vomica daily.

Palsy of The Nerve of Sight, or Amaurosis.

Palsy of The Nerve of Sight, or Amaurosis.

Causes. The causes of this affection are tumors or other disease of the brain implicating the roots of the optic nerve, injury to the nerve between the brain and eye, and inflammation of the optic nerve within the eye (retina), or undue pressure on the same from dropsical or inflammatory effusion. It may also occur from overloaded stomach, from a profuse bleeding, and even from the pressure of the gravid womb in gestation.

Cataract, the rays of light would no longer be properly refracted.

Cataract, the rays of light would no longer be properly refracted.

Cataract.

The common result of internal ophthalmia, as of the recurrent type, may be recognized as described under the first of these diseases. Its offensive appearance may be obviated by extraction or depression of the lens, but as the rays of light would no longer be properly refracted, perfect vision would not be restored, and the animal would be liable to prove an inveterate shyer. If perfect blindness continued by reason of pressure on the nerve of sight, no shying would result.

But is largely the same as for common internal ophthalmia

But is largely the same as for common internal ophthalmia

But is largely the same as for common internal ophthalmia

Treatment is not satisfactory, but is largely the same as for common internal ophthalmia. Some cases, like rheumatism, are benefited by 1-scruple doses of powdered colchicum and 2-dram doses of salicylate of soda twice a day. In other cases, with marked hardness of the globe of the eye from intraocular effusion, aseptic puncture of the eye, or even the excision of a portion of the iris, has helped. During recovery a course of tonics (2 drams oxid of iron, 10 grains nux vomica, and 1 ounce sulphate of soda daily) is desirable to invigorate the system and help to ward off another attack. The vulgar resort to knocking out the wolf teeth and cutting out the haw can only be condemned. The temporary recovery would take place in one or two weeks, though no such thing had been done, and the breaking of a small tooth, leaving its fang in the jaw, only increases the irritation.

The attacks vary greatly in severity in different cases

The attacks vary greatly in severity in different cases

The attacks vary greatly in severity in different cases

The attacks vary greatly in severity in different cases, but the recurrence is characteristic, and all alike lead to cataract and intraocular effusion, with pressure on the retina and abolition of sight.

Prevention. The prevention of this disease is the great object to be aimed at, and this demands the most careful breeding, feeding, housing, and general management, as indicated under "Causes." Much can also be done by migration to a high, dry location, but for this and malarious affections the improvement of the land by drainage and good cultivation should be the final aim.

The eye seems smaller than the other

The eye seems smaller than the other

The eye seems smaller than the other

In the intervals between the attacks some remaining symptoms betray the condition, and they become more marked after each successive access of disease. Even after the first attack there is a bluish ring around the margin of the transparent cornea. The eye seems smaller than the other, at first because it is retracted in its socket, and often after several attacks because of actual shrinkage (atrophy). The upper eyelid, in place of presenting a uniform, continuous arch, has, about one-third from its inner angle, an abrupt bend, caused by the contraction of the levator muscle. The front of the iris has exchanged some of its dark, clear brilliancy for a lusterless yellow, and the depth of the eye presents more or less of the greenish-yellow shade. The pupil remains a little contracted, except in advanced and aggravated cases, when, with opaque lens, it is widely dilated. If, as is common, one eye only has suffered, the contrast in these respects with the sound eye is all the more characteristic. Another feature is the erect, attentive carriage of the ear, to compensate to some extent for the waning vision.

The characteristic of the disease is

The characteristic of the disease is

The characteristic of the disease is

The characteristic of the disease is, however, its recurrence again and again in the same eye until blindness results. The attacks may follow one another after intervals of a month, more or less, but they show no relation to any particular phase of the moon, as might be inferred from the familiar name, but are determined rather by the weather, the health, the feed, or by some periodicity of the system. From five to seven attacks usually result in blindness, and then the second eye is liable to be attacked until it also is ruined.

The symptoms vary according to the severity of the attack

The symptoms vary according to the severity of the attack

The symptoms vary according to the severity of the attack

Symptoms. The symptoms vary according to the severity of the attack. In some cases there is marked fever, and in some slighter cases it may be almost altogether wanting, but there is always a lack of vigor and energy, bespeaking general disorder. The local symptoms are in the main those of internal ophthalmia, in many cases with an increased hardness of the eyeball from effusion into its cavity. The contracted pupil does not expand much in darkness, nor even under the action of belladonna. Opacity advances from the margin, over a part or whole of the cornea, but so long as it is transparent there may be seen the turbid, aqueous humor with or without flocculi, the dingy iris robbed of its clear, black aspect, the slightly clouded lens, and a greenish-yellow reflection from the depth of the eye. From the fifth to the seventh day the flocculi precipitate in the lower part of the chamber, exposing more clearly the iris and lens, and absorption commences, so that the eye may be cleared up in ten or fifteen days.

Other contributing causes deserve passing mention

Other contributing causes deserve passing mention

Other contributing causes deserve passing mention

Other contributing causes deserve passing mention. Unwholesome feed and a faulty method of feeding undoubtedly predisposes to the disease, and in the same district the carefully fed will escape in far larger proportion than the badly fed; it is so also with every other condition which undermines the general health. The presence of worms in the intestines, overwork, and debilitating diseases and causes of every kind weaken the vitality and lay the system more open to attack. Thierry long ago showed that the improvement of close, low, dark, damp stables, where the disease had previously prevailed, practically banished the affection. Whatever contributes to strength and vigor is protective; whatever contributes to weakness and poor health is provocative of the disease in the predisposed subject.

But refuse service to any mare which has suffered with her eyes

But refuse service to any mare which has suffered with her eyes

But refuse service to any mare which has suffered with her eyes

Yet the hereditary taint is so strong and pernicious that intelligent horsemen everywhere refuse to breed from either horse or mare that has once suffered from recurrent ophthalmia, and the French Government studs not only reject all unsound stallions, but refuse service to any mare which has suffered with her eyes. It is this avoidance of the hereditary predisposition more than anything else that has reduced the formerly wide prevalence of this disease in the European countries generally. A consideration for the future of our horses would demand the disuse of all sires that are unlicensed, and the refusal of a license to any sire which has suffered from this or any other communicable constitutional disease.

Heredity is one of the most potent causes

Heredity is one of the most potent causes

Heredity is one of the most potent causes

Heredity is one of the most potent causes. The lymphatic constitution is of course transmitted and with it the proclivity to recurring ophthalmia. This is notorious in the case of both parents, male and female. The tendency appears to be stronger, however, if either parent has already suffered. Thus a mare may have borne a number of sound foals, and then fallen a victim to the malady, and all foals subsequently borne have likewise suffered. So it is in the case of the stallion. Reynal even quotes the appearance of the disease in alternate generations, the stallion offspring of blind parents remaining sound through life and yet producing foals which furnish numerous victims of recurrent ophthalmia. On the contrary, the offspring of diseased parents removed to high, dry regions and furnished with wholesome, nourishing rations will nearly all escape. Hence the dealers take colts that are still sound or have had but one attack from the affected low Pyrenees (France) to the unaffected Catalonia (Spain), with confidence that they will escape, and from the Jura Valley to Dauphiny with the same result.

And it has been alleged that the true cause is a microbe

And it has been alleged that the true cause is a microbe

And it has been alleged that the true cause is a microbe

It is evident, however, that no one of these is sufficient of itself to produce the disease, and it has been alleged that the true cause is a microbe, or the irritant products of a microbe, which is harbored in the marshy soil. The prevalence of the disease on the same damp soils which produce ague in man and anthrax in cattle has been quoted in support of this doctrine, as also the fact that, other things being equal, the malady is always more prevalent in basins surrounded by hills where the air is still and such products are concentrated, and that a forest or simple belt of trees will, as in ague, at times limit the area of its prevalence. Another argument for the same view is found in the fact that on certain farms irrigated by town sewage this malady has become extremely prevalent, the sewage being assumed to form a suitable nidus for the growth of the germ. But on these sewage farms a fresh crop may be cut every fortnight, and the product is precisely that aqueous material which contributes to a lymphatic structure and a low tone of health. The presence of a definite germ in the system has not yet been proved, and in the present state of our knowledge we are only warranted in charging the disease to the deleterious emanations from the marshy soil in which bacterial ferments are constantly producing them.

The period of dentition and training is a fertile exciting cause

The period of dentition and training is a fertile exciting cause

The period of dentition and training is a fertile exciting cause

The period of dentition and training is a fertile exciting cause, for though the malady may appear at any time from birth to old age, yet the great majority of victims are from 2 to 6 years old, and if a horse escapes the affection till after 6 there is a reasonable hope that he will continue to resist it. The irritation about the head during the eruption of the teeth, and while fretting in the unwonted bridle and collar, the stimulating grain diet and the close air of the stable all combine to rouse the latent tendency to disease in the eye, while direct injuries by bridle, whip, or hay seeds are not without their influence. In the same way local irritants, like dust, severe rain and snow storms, smoke, and acrid vapors are contributing causes.

Aqueous fodders grown on such soils are other causes

Aqueous fodders grown on such soils are other causes

Aqueous fodders grown on such soils are other causes

The rank, aqueous fodders grown on such soils are other causes, but these again are calculated to undermine the character of the nervous and sanguineous temperament and to superinduce the lymphatic. Other feeds act by leading to constipation and other disorders of the digestive organs, thus impairing the general health. Hence in any animal predisposed to this disease, heating, starchy feeds, such as maize, wheat, and buckwheat, are to be carefully avoided. It has been widely charged that beans, peas, vetches, and other Leguminosae are dangerous, but a fuller inquiry contradicts the statement. If these feeds are well grown, they invigorate and fortify the system, while, like any other fodder, if grown rank; aqueous, and deficient in assimilable principles, they tend to lower the health and open the way for the disease.

Recurrent Ophthalmia Periodic Ophthalmia, or Moon-blindness.

Recurrent Ophthalmia Periodic Ophthalmia, or Moon-blindness.

This is an inflammatory affection of the interior of the eye, intimately related to certain soils, climates, and systems, showing a strong tendency to recur again and again, and usually ending in blindness from cataract or other serious injury.

Causes. Its causes may be fundamentally attributed to soil. On damp clays and marshy grounds, on the frequently overflowed river bottoms and deltas, on the coasts of seas and lakes alternately submerged and exposed, this disease prevails extensively, and in many instances in France (Reynal), Belgium, Alsace (Zundel, Miltenberger), Germany, and England it has very largely decreased under land drainage and improved methods of culture. Other influences, more or less associated with such soil, are potent causative factors. Thus damp air and a cloudy, wet climate, so constantly associated with wet lands, are universally charged with causing the disease. These act on the animal body to produce a lymphatic constitution with an excess of connective tissue, bones, and muscles of coarse, open texture, thick skins, and gummy legs covered with a profusion of long hair. Hence the heavy horses of Belgium and southwestern France have suffered severely from the affection, while high, dry lands adjacent, like Catalonia, in Spain, and Dauphiny, Provence, and Languedoc; in France, have in the main escaped.

The diet throughout should be easily digestible and

The diet throughout should be easily digestible and

The diet throughout should be easily digestible and

The diet throughout should be easily digestible and moderate in quantity bran mash, middlings, grass, steamed hay, etc.

Even after the active inflammation has subsided the atropia lotion should be continued for several weeks to keep the eye in a state of rest in its still weak and irritable condition, and during this period the patient should be kept in semidarkness, or taken out only with a dark shade over the eye. For the same reason heavy drafts and, rapid paces, which would cause congestion of the head, should be carefully avoided.