LIBRARY UNIVERSITY^ PENN5YL\^\NIA C 6 76- FAIRMAN ROGERS COLLECTION ON HORSEMANSHIP Digitized by the Internet Archive in 2009 with funding from Lyrasis IVIembers and Sloan Foundation http://www.archive.org/details/pathologicalhoOOcole. NO FOOT. NO HORSE.' PATHOLOGICAL HORSE - SHOEING : A THEORY AND PRACTICE OF THE SHOEING OF HORSES. BY WHICH EVERY DISEASE AFFECTING THE FOOT OF THE HORSE MAY BE ABSOLUTELY CURED OR AMELIORATED, AND DEFECTIVE ACTION OF THE LIMBS EFFECTIVELY CORRECTED. THE RATIONALE OF WHICH IS FULLY EXPLAINED AND DESCRIBED. E • BRACING AL.SO AN OUTLINE OF THE ANATOMY AND PHYSIOLOGY OF THE FOOT OF THE HORSE, AND A COPIOUS GLOSSARY, FORMULARY AND INDEX. JOSEPH BRINE COLEMAN, V. S., Member of the Royal College of Veterinary Surgeons, and member of the Veterinary Medical Association of London, England. ,~'JA y\ m'^^^MD dF ALL: 3Q0K SELLERS. CHICAGO: PuBLlbHEL- -K¥ T.4^ I .?4JUfiiOX,, ,»,r TfJE CJKFl.E-.tF HeNKY FiSH & Co., PkINTEKS AND ''/ j" j,; ','' -Pu:J^li.HEivS^ 146 Cj^AilK 5»TKEET. \lQ ) NEW BOLTON ^ ^ I CENTER Entered According to Act of Congress, in the Year 1876, in the Office of the Librarian of Congress at Washington. The right 0/ iranslatioH is strictly reserved. INDEX. Anatomy and Physiology of the Foot of the Horse — General Remarks i6 Definitions i8 External Structures of the Foot 18 The Wall 18 Composition of 19 Form of .- 19 Shape of 20 Bars, Braces, or Buttresses of 20 Laminated Internal Surface of 21 Epidermis or Cuticle of 22 Coronary Concavity 20 Angle of Inflection, Abnormal 21 Horny Sole and its Functions 2^ Peculiarities of Structure 24 Horny Frog and its Functions 24 Peculiar Properties of 25 Internal Apex of 25 Remarkable Appendix to 25 Coronary Frog-band 26 Fleming's Description of 27 Iriternal Tissues of the Foot — Its Parts Particularized 28 Bone, Chemical Constitution of 28 General Characteristics^of 29 Bones of the Foot 30 Os Pedis 30 "A MockeiV, A Delusion, and A Snare." 31 Pedestal of the Column 32 Remarkable Construction of 32 Essential Importance of the Foot 32 Os Coronae 33 Os Naviculare 33 Stellate Ligaments of 34 Cartilaginous Structures of the Foot 35 Lateral Cartilages 35 Inferior Cartilages 35 Articular Cartilage 36 Remarkable Characteristics of 37 Buflers and Gilding Surfaces 37 A Knotty Question 38 Ligamentous Textures of the Foot 39 Coronarj' Ligament 39 Functions of 39 Reasons versus Ipse Dixits 40 Periosteal and Endosteal Membranes... . 41 Sensit ive Laminae 42 An Undetermined Question 43 Interperiosteal Pad 43 Relative Weights Sustained by Fore and Hind Limbs 44 Facilis Decensus Avernus 45 Sensitive Sole 46 An Erroneous Conception Exposed 46 Mr. Fleming, Rise and Explain 47 The Solar Zone 47 Sensitive Frog 47 Functions of 49 Characteristic Structure of 48 Importance of Healthy Condition of. . . . . 49 Structure Indicates Function 49 Maximum and Minimum of Lateral Move- ments 50 Summary of Views 50 Tendons and Tendinous Textures — Par- ticularized ; 51 General Character of 51 Important Anatomical Fact 52 Flexor Tendons 52 Remarkable Mechanical Arrangements of 53 Three-fold Functions of 54 Extensor Tendons 54 Accessories of 55 The True Suspensor ... 56 Low Instep, Frequent Source of Lameness 54 Antagonizing Forces 56 Secret of Knee Action 57 Tendinous Expansions 57 Lesser Ligaments of the Articulations. . . 57 Synovial Membranes 58 Diseases of, and their Sequela; 58 A Common Error Corrected 58 The Circulatory System of the Foot 60 Arteries ■ • 60 General Remarks Upon 60 Characteristics of ... 61 \^\\\\ IV Microscopic Anatomy of ^ . - . 6i The Plantar Arteries, Description of 62 The Plantar Capillaries 64 Physiological Facts 65 Veins 66 Miciof copic Anatomy of 66 Anatomical Arrangement Described 68 Veins of the Foot Have No Valves. . . . 67 The Reason Why 68 Lymphatics of the Foot 69 Scavengers or Sanatory Agents 70 Lymphatic Glands 71 Nerves 7^ General Remarks Upon Nervous System 71 Nerves of the Foot 72 Distributive Arrangement of 72 Is the Equine Foot an Organ of Special Sensation ? 73 Prima Facie Reasons 74 Analogical Argument 74 An Objection Anticipated 75 Experientia Docet 75 Relative Sensibility of the Equine Foot . 76 Causes i>f Impaired Action 76 Sub-acute Laminitis 77 Acute Laminitis 77 General Causes — Diverse Effects 78 Injuries from Nailing on the Shoe 78 Source of Pain in the Foot 79 External Sources of Pain in the Foot 80 Muscular Spasms, or Cramp 80 Non-Inflammatory Affections 89 The " Ragged Edge " 80 Possible Cause of Stringhalt 81 Secreting Structures of the Foot— Par- ticularized 82 " Ample Room and Verge Enough " 82 Constitution of Secreting Villi 83 Fluid Elements of the Foot Particularized 83 Physical Properties of the Blood 83 Important Physiological Facts 83 Red and White Blood-Cells 84 Chemico-vital Changes in the Blood 84 Judicious Mechanical Expansion 85 The " No-Contraction and Non-Expan- sion Heresies 86 Preliminary Remarks 86 Facts versus Theories 87 Contraction as a Morbid Condition 88 The Reviewer Reviewed 88 Age not the Gage of Experience 89 " Be Just and Fear Not " 89 Essence of Gamgee 89 1 he Case Stated 90 An Important Omission Supplied 91 " Language the Key to the Sciences "... 91 Authorized Definitions 92 What Does Atrophy Mean ? 92 Value of the Word Atrophy 93 Facts versus Fallacies 93 Varieties of Feet — How Produced 94 Effects of Dry Atmosphere 94 Varieties and Effects of Contraction 95 The Invariable Cause of Qifarter-Crack . 95 The Diseases of the Foot of the Horse — Contraction— Symptoms and Treat- ment '. 97 Positive and Negative Evidence 97 Preparation of the.Foot 98 Form ^ 99 The Best Kind of Shoe 100 Nail-holes and Nailing loi Acute Laminitis — Acute Rheumatism — Acute Founder— Proximate Causes of. 103 Symptoms and Treatment 102 A Puzzling Problem 104 The Cure, " That is the Question " 104 Octogenarian Veterinarians 104 The Kind of Reception 105 Special Points in Shoeing for Laminitis. . 105 Broad's Laminitis Shoe 106 A Point of Importance 106 The Rolling Motion Expedient 106 Depletion, When Desirable 107 Constitutional Treatment 107 Chronic Laminitis— Chronic Founder — Pumiced Foot 108 Authorized Errors Combated 108 Support the Sole 108 " Stubborn Facts " versus "High^uthor- ity " ' 109 A Demonstrable Fact .^^ 109 The Why and the Wherefore . .▼. 109 Common-Sense Shoeing the Desideratum no How to shoe the Pumiced Foot no Navicular Disease — Causes and Symp- toms I" Rheumatic Symptoms n? Treatment "3 Ringbone— Etiology and Pathology 113 Treatment 113 Sidebones— Ossification of the Lateral Cartilages— Etiology and Pathology. 114 Treatment "5 Corn— Causes and Symptoms 115 The Old Theory "6 The Writer's Theory "5 V. Contraction, or Lateral Pressure, the Cause of Corn ii6 Treatment of Corn ii6 Concomitants of Contraction 117 No Bar-Shoes Necessary for the Cure of Any Corn 117 Suppurating Corn 117 Nothing Like Expansion of the Quarters to Cure Corn n8 Toe-Crack and Quarter-Crack— Etiology' and Pathologj' ii8 Contractionists, and Non-Contractionists 119 Solid Proofs Wanted, Not Fallacious Ar- guments 119 The True Rationale of Qiiarter-Crack . . 120 Centers of Rotation, or Motion 120 Correlative Movements 121 Rationale of Treatment 121 A Sine Qua Non 142 An Exploded Fallacy 122 Quarter Before, Toe Behind 125 The Cause, Par Excellence 123 What to Do, What Not to Do. 12.^ False Quarter— Shelly Foot— Seedy Toe. 124 False Quarter 124 Treatment.,. 125 Shelly Foot laS Treatment 125 Seedy Toe — Special Characteristics 126 General Treatment 127 Grease — Scratches— Chapped Heels- Thrush — Etiology and Pathology . .. 128 Fatty Follicles and Their Functions 128 Crowding and Dwarfing the Tissues 128 DiflBcult to Misunderstand 129 The Machinery out of Gear 129 Bad Enough at That 130 Treatment of Grease or Scratches 130 Treatmei^^f Thrush 131 The All-I^lortant Adjunct 131 Treatment of Canker 131 Some Cures Contrary to All Expectation 131 Atrophy of the Foot— Dry Rot 133 Contraction, Both Cause and Conse- quence 133 General Principles of Treatment 133 Accidental Injuries 133 Calking the Instep 134 Characteristics of Quittor 134 A Remarkable Resemblance 134 The Most Powerful Adjunct 135 Tetanus or Locked-Jaw — Etiology and Pathology 135 Mysterious Intertransmutations of Disease 136 Facts of Pathology Concurrent, or Predisposing Causes Invaluable Adjunctive Measure Slringhalt — A Mysterious Malady Notes and Queries Peculiar Mechanism of the Hock-Joint.. Does Stringhalt Constitute Unsoundness ? Professor Spooner's Hypothesis Percival's Opinion Microscopical Research Professor Spooner's Final Judgment Physiological Attribute of the Hock- Joint Busteed's Belief Professor Spooner's Strictures -Dr. Busteed's Claim as a Discoverer E.xperimental Facts A Curious Coincidence The Writer's Suggestion Summarized Statement of Author's The- ory Summary of Changes Incipient Contraction Advanced Contraction Ossification of Lateral Cartilages Laminitis Drop-Sole, or Pumiced Foot Navicular Disease Ringbone Corns Quark-Crack Toe-Crack False Quarrer Shelly-Foot Seedy-Toe Scratches Thrush of the Frog, Canker of the Sole General Atrophy of the Foot Accidental Injuries Treads Bruises Injuries from Calking Quitters Suppurating Corns Picking Up Nails Injuries Connected With Shoeing Constitutional Complaints Tetanus, or Locked Jaw Pneumonia Pleurisy Gastritis Enteritis Gastro-Enteritis X37 137 V^S 139 140 140 141 141 142 142 142 143 143 143 144-- 144 M4 145 147 147 147 147 147 147 147 148 148 148 148 148 149 149 <4 149 149 149 149 149 149 149 149 149 149 149 149 149 149 149 149 149 149 -VI. Skin Affections 149 Sweeny, or Atrophy of Muscles 150 Irregularities of Gait and Action 150 Conclusion 151 FORMUL.C : Poultices and Poultice Boots 152 Fomentations for Different Forms of In- j"ry 153 Lotions for Various Purposes 154 Liniments and Embrocations for Sprains, Bruises, etc 156 Liniments and Salves for Canker, Thrush, «'<= 157 Powders for Scratches, Canker, Thrush, ^»c 159 Powders for Cleaning Foul Ulcers, etc. . . 160 Blistering Applications for the Removal of Splents, Spavins, Ringbones, Side- bones, Bony Enlaigements, Thick- ened Tendons, etc i6i Hoof Dressings— Their Use and Abuse. . 162 Hoof Stimulants 163 Hoof Salves 164 Hoof Stoppings for Sole and Frog 164 Constitutional Treatment 166 Preliminary Remarks 166 Glossary 170 Special Notification 179 Testimonials 181 How to make a Book 18 r The Play without the Part of Hamlet. . . 181 Acknowledgments 182 Unexceptionable Testimony 182 Letter from Addison Doughty 182 Letter from R. C. Anthony 184 The Dilator i85 The Book and the Instrument — Terms. . 187 APOLOGETIC AND EXPLANATORY, The author of this work is fully conscious of some errors of omission as well as commission to be found within its pages, although he deems them of minor importance, when compared with the really valuable and useful practical information it con- tains, upon a much neglected but highly important branch of veterinary science and art. It was intended that its pages should have been enriched with first-class engravings illus- trative of the doctrines and the practice taught. These, how= ever, the exigencies of professional duties, and other circum- stances, would not admit of being executed in a manner that would be deemed satisfactory to the public, or the author, within the limits of time at the latter's disposal. He trusts that his desire for the issuance of his work during the most momentous celebration of human progress of modern times, may, to some extent, further excuse this omission, as well as the reduction of the original price — Five Dollars with illustra- tions, to Three Dollars without them. It is the author's intention to fully complete his work in a future edition, and^*J to make it worthy in every respect of the age of enlightened^l^ progress in which we live ; of the great epoch now being celebrated ; of the Country, par excellence^ which as yet, has exhibited the highest developement combined with the greatest utilization of speed in the noblest of all animals, the Horse ; and of the important protessson to which he has the honor to belong. INTRODUCTORY. HUMANE SOCIETIES AND IMPROVED HORSE-SHOEING. Amongst the various secondary objects which Humane So- cieties, the world over, propose to themselves to attain in order to carry into effect their highest benevolent intentions towards the inferior order of created beings, which are associated with, or subject to, the service of mankind within the different spheres of civilization, there is none I deem of more transcending im- portance to the best interests of society, in subserving the noble aims, greater and lesser, which those societies have in view, and the well being of the quadruped under consideration, th^n improved methods of shoeing horses^ whether for the purpose of preventing disease and lameness, or for removing or amelior- ating those abnormal conditions when present. The full meas- ure or complement of all that is possible in these directions, ought to be accomplished. The writer of the following pages on pathological horse- shoeing, deeply impressed with this view, as well as actuated by a profound conviction of personal duty, earnestly desires to enlist the active sympathies and assistance of the above socie- ties in every civilized community on behalf of what he regards as his mission of mercy to the victim of the most unaccount- able ignorance of his necessities, in the management of one of his most essential organs of usefulness ; yet, withal, an indis- pensable and invaluable adjunct of civilization everywhere. About three years since, the Scottish Society for the Preven- tion of Cruelty to Animals, awarded prizes "for the best and most practical essays on horse-shoeing, in connection with the comfort and soundness of the horse." Upwards of forty essays B 10 were sent in, the chief prize being awarded to G. S. Fleming, Esq., of London. ' Mr. Fleming's essay contemplates only the correct principles upon which a sound foot should be shod. It left untouched the wider and more hnportant question as to how the feet of horses in a diseased and semi-diseased conditions should be shod ; 7?iore important because of horses in actual service at the present time, I do not think that one in twenty may be said to have a perfectly sound foot; and still 77iore i?n- portant, inasmuch as the methods or principles involved in restoring a diseased foot to healthy conditions, will point, in- fallibly, to the manner in which it should be shod to preserve healthy conditions, while no amount of ordinary horse-shoeing for the sound foot will teach methods of shoeing for the un- sound foot. The term, pathological shoeing, refers to shoeing diseased feet ; physiological shoeing, to shoeing the sound foot. Some prefatory remarks to Mr. Fleming's essay, made by the Secretary of the S. S. P. C. A., have a peculiar appropriateness here. He says : " It is a painful reflection, that the advance of civilization seems ever to be accompanied by certain evils, and in no instance is this more marked than in the terrible amount of suffering unnecessarily endured by the Horse. This ani- mal, pre-eminently the most useful to man, is the one upon which is inflicted, either wantonly, or through sheer ignorance, or thoughtlessness, the greatest amount of cruelty. The re- cords of all humane societies, show that of prosecutions for cruelty to animals, an overwhelming majority refer to the horse, and of these a large proportion* are for working horses, while suffering from lameness in one form or another. So frequent are such cases, that observers have concluded that its preva- lence must result from some specific cause; and not unnatu- rally attention has been directed to the various modes of man- agement practiced relative to the horse's foot, to the manner of shoeing, and in particular to the way in which the hoof is prepared for the shoe." Here, then, is an illustrious prece- dent, if any were needed, in the most progressive city in the world, whose collective characteristic is to lead rather than to follow ; for the Chicago Branch of the Illinois Society for the 11 Prevention of Cruelty to Animals, upon which to take action upon a question of extreme moment, directly to the well-being of the horse, whose natural rights it is the morally and legally recognized guardian and advocate; and, incidentally, to the main objects to attain which, the society has been called into existence, and to society at large. I respectfully suggest, that a committee of this Society be appointed to inquire into the value of the modes of treatment enunciated in this work. This can readily be determined by testimony and experiment. I am prepared to show by the testimony of gentlemen, owners of horses, and of well known horsemen of this city whose horses I have treated, and some of whom, moreover, I have in- structed in my processes and plans of treatment, that the majority of all the diseases incidental to horses' feet are curable by the means I recommend, and many of them by no other means; that they have the merit of being simple and easily ac- quired, and their application easy, by any man of intelligence ; that there need be no pain consequent upon their application, but that, in many cases, they occasion an immediate relief of pain and lameness. By experiment, I propose to prove beyond a peradventure, that in all the varieties of foot affections, with but very few exceptions, the immediate effect is beneficial, and the ultimate result in a vast majority of lamenesses from diseases of the foot, an absolute cure, if simple rules concerning man- agement and shoeing are observed during the progress of re- covery. If this can be shown to the satisfaction of a com- mittee of this Society, can a doubt exist as to the course the latter ought to pursue in regard to an endorsement of the treat- ment recommended and taught in this work .? PREFATORY The publication of this work has arisen out of the expression of a want on the part of my pupils for a remembrancer, or guide, in the application of the principles and practice of the treatment I have adopted and recommend for the adoption of others, as the most rational, and the most successful of any that I am acquainted with, or even heard of. The first intention was to limit its issue to my pupils who had been fully instructed in the theory and practice of the views it embodies. A fuller consideration, however, of the benefits that would accrue to society, aye, to the world at large, in the diminished sufferings, a fuller utilization, and in the enhanced pleasure and profit arising from the employment of one of the most useful of the domestic animals, namely, the horse, has determined the writer to give a wider dissemination to his views and methods of treatment for the diseases incidental to the foot of that animal ; to devote his entire energies to the work of personal instruction which he has begun, and by rescuing those operations from the domain of empiricism and selfish secrecy, to give them their legitimate place in the category of useful medical appliances. It is a fact but too patent to the observation of every think- ing person having any interest of humane sentiment, pleasure, or pecuniary profit in the well-l^eing of the horse, that the foot- diseases of this animal are out of all reasonable proportion, in excess of those affecting him in other respects, and that the foot of the horse and its diseases, notwithstanding the numer- ous ponderous volumes that have appeared from time to time since the establishment of the Royal Veterinary College of Lon- don, England, over three-quarters of a century since, is still the least understood, and the best, or worst abused organ of the whole animal economy. 13 Every humanitarian who embraces within his merciful re- gard every creature whose existence is not inimical to his own, whose common feelings of sympathy for the speechless victims of modern civilization, constitute a platform of union and effort, for the one common purpose of preventing, or mitigating those sufferings, as far as they have the authority and power con- ferred by the law to do, will assuredly be interested in any painless, or even comparatively painless process of treatment by which the sufferings of horses which arise from the morbid condition of their feet, may be materially abridged ; that in some instances acts almost magically in the relief of pain, and in all cases exerts its ameliorating influence gradually, but surely, and perceptibly, day by day. The scientific veterinarian owes a positive duty to society and to the profession of which he is a member, besides hav- ing a personal and pecuniary interest therein, to investigate any, and every mode of operation that promises to enable him to cope more successfully than he has hitherto done with the morbid conditions of the pedal extremities of the animal of whose physical welfare he is the recognized protector and phy- sician, which seem to have baffled and defied the acutest veter- inary pathologists of every age and country to account for and to overcome. Has he not an all important interest, the value of which can scarcely be estimated, in a theory, and such a prac- tical verification of it, that throws a clear and unexpected light upon causes of morbid conditions heretofore obscure, and a theory and practical measure moreover, the truth and value of which he can so readily demonstrate for himself in a variety of cases, and be master of its application in a few hours? Hitherto, I confess, I have been extremely reticent upon the subject of my modes of treating diseases of the feet of horses. Now that I have assumed the role of teacher, and have de- voted my time and energies to the vocation of teaching, I am willing to impart the special information I possess freely and unreservedly to every veterinary practitioner of whose ability I am satisfied to do justice to the operation I recommend. 14 It is not less the duty and the interest of the horse-shoer, who aspires to superiority in his important and useful calling, to acquire a correct, if not a profound knowledge of the nature and functions of the structures he is called upon to operate, in order — 1. That he might the more intelligently co-operate with the owner of the horse, or the veterinary surgeon having a case in his charge. 2. That he may justly be entitled to the confidence of his employer who may be unable, or unwilling, if able, to give any special directions in the matter. 3. That he may be able to distinguish between normal and abnormal developments, or healthy and unhealthy conditions, to become familiar with, so as to be able to detect readily the first advances of a departure from healthy conditions, or the natural conformation of the organ it is his particular pro- vince to conserve and protect ; and moreover that he may have, and be able to apply that special knowledge which will enable him to counteract and check such advances. The shoeing-smith who possesses these qualifications has in his hands a powerful lever of personal advancement in his call- ing, and the ivhip /land of his fellow craftsman not so well in- formed, upon the road to distinction and wealth. A clear understanding of the subject can be gained by any intelligent smith in the course of a few hours private, or other instruction, by the aid of specimens, diagrams, etc. His oppor- tunities for demonstration are of course the best, as he can be instructed and initiated into the modus operandi in his own workshop. Every smith, if possessed of candor, after witness- ing the results of the operation for Contracted Feet, Corn, Quarter-crack, and in Founder and Navicular Disease are so pleased and surprised that they exclaim in the spirit, if not in the precise language of the philosophic Hamlet : " There are more things in heaven and earth, Horatio, Than are dreamt of in our philosophy.'' I claim no special merit on the score of originality as to the facts and the main feature of the practice on which my methods 15 of treatment are based. There is nothing new in the practice of dilating the foot for a contracted condition of that organ, though I incline to the opinion that something new will be found in its application, and in the theory which embraces and explains the etiology and the rationale of cure of every specific disease of the foot, and throws new light on some of the mys- terious constitutional maladies of the horse. The process, limited to the correction of contraction, was recommended by La Fosse, a celebrated French equine path- ologist, over a century since, and his successors at the Veter- inary College of Toulouse, have issued a brochure on the sub- ject within the last decade; still, however, limiting its utility to contraction. Horse-shoers everywhere, but especially in the country districts, occasionally pry open the horns of the shoe with a common smith's tongs. I have experimented and investigated, and have found that there is literally no disease, and scarcely a condition of the equine foot to which it is not applicable, whether it is for the prevention or cure of disease, or for the correction of faulty action, and per consequence, the development of speed. This universal applicability has revealed the true character and causes of some diseases about which controversies have raged and spent themselves in vain for the last three quarters of a century, as far as a solution of the questions in dispute was concerned, and of others which have hitherto been very diffi- cult of cure, but of which the difficulties are now completely overcome. In short, the long sought for theory, which most writers on veterinary pathology have thought would in time be found, that would explain and harmonize many conflicting opinions and recorded observations upon these matters, and show the true sequence of the causes and effects which pro- duce the various disorders of the foot of the horse, in the wri- ter's opinion, has been found, and is now submitted to the judgment of the veterinary profession and the world — for the first time. AN-ATOMY AND PHYSIOLOGY OF THE FOOT. GENERAL REMARKS. To attain anything like a full and clear conception of the economy of the foot of the horse, its various component parts, whether internal or external ; their structural organization, aiTd the uses for which they are designed ; the laws that govern healthy function ; the phenomena of disease, and the rationale of cure, should be studied very attentively. "There is no royal road " to the perfect mastery of this subject ; but it is one whoever travels with diligence, whether for pleasure or profit, will soon be led to a strong vantage ground of usefulness to society, that will enable him to accomplish an incalculable amount of benefit -for the horse, and therefore for his owner, and incidently to advance in manner and degree, but little sus- pected, the best interests of humanity and civilization. Anything more than a brief outline of the anatomy of the integrant parts of the foot, whether internal or external, would lead me far beyond the limits assigned me by the scope of this work or the patience of my readers. Indeed, I would much prefer the discussion of hypotheses, the investigation of causes, and the practical application of remedies, to the dry details of anatomy. They are, however, not barren of results, since they afford the only foundation upon which the science of therapeutics can be built. If, therefore, we would build for per- manence, we must lay the foundation broad and deep in the facts and teachings of anatomy and physiology. n The importance of a knowledge of the peculiarities of form and structure of the various organs and tissues of which the foot is composed, will be best appreciated when disease has in- vaded them, and every available means are being employed to combat the invader. On such occasions I am accustomed to say that the case requires, and should have, every chance there is in its favor, however apparently trifling, to expedite recovery. An apparently trifling chance will frequently turn the scale for^ or against, the animal's recovery, and the reputation of the practitioner. The amateur student may not be aware that considerable diversity of opinion exists not only in the great body of the veterinary profession, but even amongst its leading teachers and writers ; not only upon the functions of the different organs that compose the foot, but of those of the pedal organ itself. Even the anatomical structure of the foot, usually deemed a science of fact and of demonstration, so prolific is the foot of the horse in contrariety of views, does not command absolute unanimity of opinion. As to the specific diseases of the equine foot, there are still wider divergencies of sentiment and opinion concerning their causes and treatment amongst the literary luminaries of the profession. These, however, will be reviewed in the section devoted to the consideration of the diseases of the foot. It will be seen, by and by, what an important connection there is between a correct knowledge of healthy functions of the several parts of the foot, and the right application of prin- ciples for the prevention and removal of its morbid conditions. A study of the physiological laws can alone afford a satis- factory basis for the consideration of the phenomenal changes which inevitably succeed a violation of these laws. The better the laws of health, and the causes and symptoms of disease are mastered, the reasons for, or against, any line of practice that may be recommended, can be the more judiciously reviewed^ and adopted or rejected, with just confidence. 18 DEFINITIONS. The foot of the horse admits of two definitions : the common, and the anatomical. The common implies the horny extremity of the limb, and the tissues contained within it; the anatomical applies to all the structures beyond the lower joint of the knee. It is in its common acceptation that I shall use the term foot. I do not for the present propose to enlarge my scope of inquiry beyond the limits implied in this term, except by way of explanation or illustration of doctrine concerning the func- tions of the pedal organ. Indeed, I fear that I shall be found, even within these limits, to tax the endurance of my readers very considerably, whether professional or not, as I find it im- possible to do justice to the numerous topics of discussion that arise out of a consideration of the foot of the horse in its varied aspects of structure and function by any very summary style of treatment. THE EXTERNAL STRUCTURES OF THE FOOT. The external structures of the foot, regarded as a whole, is called the hoof. The hoof may be conveniently divided into the wall, sole, bars, frog, and frog-band. 1, Figure i. — Vieiv of the Hoof -when separated from its internal attachments, a a a. The Wall ; b. The Coronary Concavity; c. The Horny Plates or Laminae; dd. The internal Commissures: e. The Horny Frog ; /". The Internal Prominence of the Frog corresponding to the External Cleft ; g g. Inner Surface of the Sole ; h. The Frog-band. 19 THE WALL is that portion of the hoof which is visible when the horse is standing. The different portions of the wall, viewed exter- nally, are respectively denominated the toe, the inner or outer toe, the quarters and the heels; terms sufficiently self-explan- atory. COMPOSITION OF THE WALL. The great body of the wall is composed of a dense fibrous mass, the fibres being bound together by a glutinous material called the horny matrix. The internal surface consists wholly of the horny matrix, and is laminated. FORM OF THE WALL. The wall presents some peculiarities of form, which it is not unimportant to be familiar with. These are noticed by Turner in the following paragraph : " On inspecting the unshod foot of a four-year-old colt (which is fully developed at that period of life), it has been the fashion for veterinary writers to consider its ground surface as a circle. To this I have much objection, having always been struck by the great inequality of its two sides, not only as to the addi- tional thickness of the wall of the outer quarter in comparison to the inner, but the still greater difference in compass or cir- cularity; the outer quarter furnishing far more than is neces- sary to form the half-circle, while the inside is generally much less than a semi-circle. This bulge, or fine luxuriant growth of the outside quarter is generally most apparent toward the heel, not only forming a much broader basis of support for the superstructure than the inside, but also one of immense strength. The inside column of wall being less strong, and yet placed more immediately under the centre of gravity, it appears to me quite obvious that Nature intended the outer quarter should serve as the main prop of support, whilst the inside quarter, in proportion to the weight and speed of the animal, should expand and oppose concussion." 30 THE SHAPE OF THE WALL-DIFFICULT TO DESCRIBE. As to the question whether the general form of the foot be cylindrical or cone-shaped, I agree with Spooner, that in some horses no doubt the feet are cylindrical ; but as in the great majority of hoofs, and particularly those which we consider the best, the circle at the upper part is less than one at an equal distance lower down, we shall be more frequently correct if we describe it as the " frustum of a cone, the base and summit of which have been intersected by two oblique planes." The fact, however, is, that no mathematical figure can correctly describe the exact shape of the foot, for viewing it in front we may pronounce it conical^ whilst at the same time its lateral aspect may be that of a cylinder. THE CORONARY CONCAVITY. On the inside of the upper margin of the wall is to be seen a concavity, about three quarters of an inch in depth, and extend- ing throughout the entire upper circumference of the wall. This is named the Coronary Concavity, and by some the Coronary Ring. This concavity is for the repose of the organ which secretes the fibrous, and therefore the principal portion of the wall, and is called the Coronary Secretary Substance. On the surface of the Coronary Concavity may be seen, by the naked eye, a vast number of minute perforations, which receive the secreting villi of the Coronary substance. Quoting Haycock : " These are the commencement of the horn tubes which are continued from the top to the bottom of the hoof; the hoof, in part, is a series of minute cylinders or hollow tubes. These tubes exist in im- mense numbers, are placed side by side, and traverse the entire length,' or rather depth of the horny mass. The animal, strange as the statement may appear, stands and travels upon thou- sands of cylinders, all arranged with extreme regularity, and held together by a common glutinous medium, in which is de- posited the peculiar pigment giving color to the hoof." THE BARS, BRACES, OR BUTTRESSES OF THE WALL. Another portion of the foot has received the names of Bars. Spooner describes them as a continuation of the wall, being 21 similar to it in their structure and appearance. The point where the inflection or doubling inwards of the wall takes place is usually called the angle of UiflectioTi. The Bars extend for- wards and inwards towards the apex or point of the frog, ter- minating just before reaching it. The Bars are about the same thickness as the wall is at the quarters, and their greatest depth is about an inch, gradually lessening toward their ter- mination. The bars act as braces or buttresses in forming and supporting the heels of the wall upon which the shoe rests. The wall and bars constitute the boundary of the sole with which they have a strong and intimate union. NO ANGLE OF INFLECTION IN A NORMALLY SHAPED FOOT. In a normally healthy foot, the inflection, where the bars spring from the wall, is of a rounded rather than an angular form. Whenever the inflection exhibits a strongly marked angular form, I regard it as a departure from the standard or normal shape, induced by a contracted or shrunken quarter. It is the angular form that produces the condition termed Corn. I, therefore, cannot consider the term, angle of inflection^ so fre- quently used by writers upon the foot, as correct, if applied to a normally shaped foot. Figure 2. — A Foot with open heels and rounded inflections. Figure 3. — A Foot with contracted heels and angular inflections. THE LAMINATED INTERNAL SURFACE OF THE WALL. The entire inner surface of the wall from the lower edge of the coronary concavity to the line of junction of the wall with the sole is covered by a large number of closely set, long, thin, 22 narrow leaves, or plates. Their form, and the nature of this substance has given them the name of horny laminae. In the detached hoof, it will be seen that one longitudinal edge is free, while the other is united to the wall. It is, indeed, a por- tion of the wall itself, frilled as it were into the form we view it. By means of these plates, averaging about 500 in number, the wall is attached to the internal portion of the foot, namely, to the pedal bone, and it extends to the lateral and inferior car- tilages. Besides forming an attaching medium of great strength and tenacity and large extpnt, they subserve other important purposes which will be referred to a little further on when re- viewing these functions more particularly. THE EPIDERMIS, OR CUTICLE OF THE WALL. A not unimportant constituent of the wall is its extreme ex- ternal coating. Physiologists tell us that the normal hoof is covered by a layer of a silicious material resembling that upon the outer surface of straw, and that it fulfils a similar function to the wall of the foot as that of the epidermis or cuticle, to the dermis or true skin. The healthy foot is able to secrete and maintain a degree of moisture compatible with the exis- tence of toughness and resiliency in its outer structures, and any excess or deficiency of moisture is equally pernicious to a healthy foot. The former is promoted by the injudicious use of the knife and rasp, conjoined with soaking, stopping, poulticing, etc.^ while the latter is the result of the same unreasoning process of rasping and paring, with the soaking and stopping omitted. Whenever the epidermic covering is removed by the rasp, as is too frequently the case, undue evaporation takes place, and the hoof becomes the very opposite of what it should be, under the combined influences of inordinate exhalation of moisture, and the heat of the sun, or an unusually dry atmosphere. The subject is suggestive of much more that might be said, but must be reserved for future consideration. 23 THE HORNY SOLE AND ITS FUNCTIONS. The horny sole, the organized foundation, the chief weight- siistainer of the animal frame, constitutes the whole of the plantar surface, not occupied by the edge of the wall, includ- ing its inflections, the bars, and the external frog. Its line of junction with its boundary wall may be traced by a white line or zone, which Mr. Fleming, I believe, has been the first to notice in print. A detached sole presents the remarkable peculiarity of a deep indentation in the general form of an isosceles triangle^ its base being placed posteriorly, and its apex extending fully two-thirds of the distance from its base to the anterior margin' of the sole. Figure 4.— External View of the Horny Sole. Microscopic anatomists describe the horny sole as fibrous in its inner substance, the fibres taking an oblique direction for- wards and downwards, corresponding to that of the fibres of the wall, and gradually changing into squamous incrustations, somewhat similar to the epidermis of the skin as it approaches its external limits. The horny sole is secreted by the vascular and sensitive sole, and in the same manner as the wall is secreted by the coronary band, by tufts or villi that penetrate the horny fibres. The wall wastes by attrition when the animal is unshod ; the sole and the frog, by exfoliation. 2i Of other peculiarities of construction of the sole, I prefer to give them in the words of an able disquisitionist upon the equine foot, Professor Gamgee, Senr. THE HORNY SOLE-PECULIARITIES OF STRUCTURE. " The sole is thickest at, and is strongly connected anteriorly, and in its two posterior terminations, where it is so strongly inverted by the inflections of the wall, as to be incapable of direct dislocation by any means, whilst the parts remain in their integrity, viz., not cut away or weakened. The inflected wall, which according to prevailing notions is called 'the bars,' constitutes for all essential purposes an inner wall, a con- tinuation of the outer wall ; these minor inflections have no such abrupt terminations, as their outer appearance at first sight indicates, or as seems to be the case by the laminated attaching inner surface; the same inflected wall forms the inner boundary of the two lateral divisions of the sole poste- riorly, and it is by these that the strength of the sole is con- tributed, and its arched form perfected." THE HORNY FROG AND ITS FUNCTIONS. The Horny Frog is triangular in shape, and occupies the triangular cleft in the sole. Quoting from Fleming : " In the middle of the posterior part is a cleft, which in the healthy state should not be deep, but rather shallow and sound on its surface. In structure, this body is also fibrous, the fibres pass- ing in the same direction as those of the other portions of the hoof; but instead of being quite rectilinear like them, they are wavy or flexuous in their course, and present some micros- copical peculiarities, which, though interesting to the compar- ative anatomist, need not be alluded to here. The fibres are finer than those of the sole and wall, and are composed of cells arranged in the same manner as elsewhere in the hoof; they are formed by the villi which thickly stud the face of the mem- brane covering the sensitive frog." 25 PECULIAR PROPERTIES OF THE FROG. The substance of the homy frog is eminently elastic, and corresponds in the closest manner to the dense elastic epider- mic pads on the soles of the feet of such animals as the camel, elephant, lion, bear, dog, cat, etc. ; and which are evidently designed for contact with the ground, the support and protec- tion of the tendons that flex the foot, to facilitate the springing movements of these creatures, and for the prevention of jar and injury to the limbs. In the horse's foot, the pressure of this thick, compressible and supple mass of horn at the back of the hoof, in a healthy unmutilated condition, and permitted to reach the ground while the animal is standing or moving, are absolutely essential to the well-being of that organ, more especially should speed, in addition to weight-carrying be exacted. The frog like the sole exfoliates, or becomes reduced in thickness at a certain stage of its growth ; the flakes are more cohesive than those of the sole. THE INTERNAL APEX OF THE HORNY FROG. It must be remarked, however, that this exfoliation of the sole and frog only takes place when the more recently formed horn beneath has acquired sufficient hardness and density to sustain contact with the ground, and exposure to the effects of heat, dryness and moisture. The cleft of the frog penetrates some distance into the foot and terminates in a horny prominence which I am accustomed to regard as the internal apex. This prominence, by its pointed character and upward direction when one or both heels are contracted or shrunken and the frog is of small dimensions, plays a very important part in the production of lameness. This, however, I will not dwell upon here. A REMARKABLE APPENDAGE TO THE FROG. The frog-band or stay was first dissected out and described by Bracy Clark. Mr. Fleming designates it by the more technical c 26 term " Periople." I at one time shared the opinion of my pre- ceptor in anatomy, that the frog-band was more a matter of fancy than of fact, and that many ingenious carvings could be made out of a horse's hoof. I have, however, a very well marked specimen in which the band shows its true character without any carving whatever, by the simple process of drying and partial separation. A thin leather strap made to encircle the hoof around its superior border, each end embedding itself into the substance of the frog, it seems to me, may convey an idea of its structure and uses. To my view it is precisely anal- ogous in its purposes to those of the strap that embraces the human instep and gives support to a clog^ that is sometime worn, particularly by ladies. A few moments reflection upon the slender character of the attachments of the frog at its pos- terior portions will show the necessity for the existence of some such an arrangement as this. The following is Mr. Fleming's description of this structure : "The Coronary Frog-Bandy or ''Periople^ is a continuation of the more superficial layer of the skin around the coronet and heels, in the form of a thin, light colored band, that descends to a variable depth on the outer surface of the wall, and at the back part of the hoof becomes consolidated with the frog, with which it is identical in structure and texture. It can be readily perceived in the hoof that has not been mutilated by the far- rier's rasp, extending from the coronet, where the hair ceases, to some distance down the hoof; it is thickest at the commence- ment of the wall, and gradually thins away into the finest im- aginable film as it approaches the lower circumference of this part. When wet it swells and softens, and on being dried shrinks, sometimes cracks in its more dependent parts, or be- comes scaly. The fibres composing it are very fine and wavy, as in the frog; they likewise spring from villi which project from the true skin immediately above the "coronary cushion." The use of this band would appear to be two-fold ; it connects the skin with the hoof, and thus makes the union of these two dis- similar textures more complete, its intermediate degree of den- 2Y sity and its great elasticity admirably fitting it for this office; and it acts as a covering or protection to the wall at its upper part, where this is only in process of formation, and has not sufficient resistance to withstand the effects of exposure to the weather. The greatest thickness and density of the band cor- responds to the portion of the wall in which the z///// or vascular tufts are lodged, and here the horn is soft, delicate, and readily acted upon in an injurious manner, by external influences." Elsewhere he writes of its uses, and abuses : *' The thin, semi-translucent horn that extends in a somewhat wide, whitish-colored band, around the upper band of the foot, is chiefly intended by Nature, I think, to protect the fibres of the wall from the effects of external physical influences, such as heat and dryness, while they are being secreted, or so immature as to be incapable of resisting these influences ; for it will be remembered that the wall is formed at the coronet, and this covering guarantees, not only the integrity of the newly-made horn-tubes, but also maintains the secreting vessels that enter them, in a healthy condition, and competent to supply fresh material for wear. The destruction of this band, and the rasp- ing of the fibres beneath it, is detrimental to the healthy secre- tion of the wall fibres, and leads to the same result that paring the. sole was shown to do: shrinking of the horn tubes con- taining the tufts of vessels, wasting of these, a diminished supply of horny material in consequence, and a thin brittle wall that scarcely appears to grow down at all, in depth or thickness, and barely allows a shoe to be attached to it. Sand- crack and other diseased conditions of this part of the hoof are mainly due to this cause." To all of which I yield an unqual- ified assent, excepting the last clause. Ascribing as I do the chief proximate cause of quarter-crack to contraction of the lower part of the quarter, and outward pressure upon the upper, I am willing only to accept brittleness of hoof, etc., as. predisposing or secondary causes. 28 THE INTERNAL TISSUES OF THE FOOT. ITS PARTS PARTICULARIZED. Having described the component parts of the hoof, or exter nal portion of the foot, we will proceed to the consideration of the internal structures or tissues of that organ. The first division of these is into solids and fluids. Of the solid constituents there are bones, cartilages, ligaments, blood- vessels, nerves, absorbents, and secreting glands. The Fluid elements comprise the blood, synovia, marrow, lymph, and the various glandular secretions. The Bones consist of the pedal, navicular, and the coronal. The Cartilages include the articular, the lateral and inferior. The Ligamentous Structures comprehend the tendons of muscles that are inserted into the bones named, the lateral and other ligaments of the foot-joint, as well as the synovial, cap- sular, periosteal, and perichondrial membranes, and the fibro- elastic structures of the wall sole and frog. The Blood-vessels embrace the arteries, capillaries and veins. The Nerves — sentient and motory. The Absorbents — superficial and deep-seated. The Secreting Textures — of the wall, the sole, the frog, the frog-band, the solar zone, the sebaceous follicles, and the per- spiratory exhalents. The fluid elements are sufiiciently categorized. DESCRIPTION OF THE BONES OF THE FOOT. CHEMICAL CONSTITUTION OF BONE. Before entering upon the descriptive anatomy of the bones, a brief allusion to the composition and characteristics of bone substance may not be unprofitable, as assisting to throw light on some of the diseases of bone, of which we have several conspicuous examples in the organ under consideration. 29 The two principal constituents of bone are cartilage and phosphate of lime ; the proportions of the former being about 29 to 34 per cent., and that of the latter, from 50 to 60 per cent, of the entire bone. The bone-earth may be dissolved out by dilute hydrochloric acid (one part of strong acid to five parts of water). The cartilage remains unaffected and retains the form of the bone. This is really a curiosity which may easily be obtained in the manner indicated. The following analysis of the bone of a healthy horse is to be found in Bowman's Medical Chemistry. In every 100 parts there is Phosphate of Lime 54-37 Carbonate of Lime 12 . 00 Phosphate of Magnesia i .83 Soluble Salts 0.70 Cartilage 27 . 99 Fat.... 3. II [00.00 In certain morbid conditions of bone remarkable changes take place in their chemical composition, in which the earthy matters are so deficient that they no longer possess the rigidity and strength necessary for sustaining the weight of the body. A deficiency of the cartilaginous material would render the bone brittle, and liable to fracture upon the slightest occasion. The former condition is called mollities ossium^ the latter /r^^/- litas ossium. I have met with examples of both conditions in all three bones of the feet that I have named. In healthy bone phosphate of lime predominates; in exostoses, carbonate of lime is the predominating ingredient. GENERAL CHARACTERISTICS OF BONES. Bone, when recent, is covered by a very vascular membrane called the periosteum. The periosteum is a bed for the ramifi- cation of blood-vessels, nerves, absorbents, and is prolonged into the Haversian canals, and connects itself with a similar membrane within the bone named the endosteum. " Bones 30 are endowed with vitality, are nourished, grow, waste, and are repaired, and undergo various mutations according to the age of the animal, and they are subject to diseases analagous to the soft parts." — Dadd. PARTICULAR DESCRIPTION OF THE BONES OF THE FOOT. Enumerating the bones of the foot in the order of size, the number either wholly or partially within the foot are three, namely : 1. The Os Pedis. 2. The Os Corona. 3. The Os Naviculare. These three bones enter into the formation of the foot-joint. I. The Os Pedis, Foot or Coffin-Bone. The OS pedis or coffin-bone belongs to the class of irregular bones; it possessing such a remarkable complexity of form. Viewing it in front, its superior outline presents an eminence somewhat like a pyramid in shape, and is therefore called the pyrainidal process. This process receives the insertion of the tendon of the Extensor Pedis muscle by which the foot is ex- /^«^^^ during action. Immediately beneath the articular sur- face that corresponds to that of the navicular bone, the tendon of the flexor pedis perforans is inserted. The office of this muscle, as its name implies, is to flex the foot. The whole of the anterior surface is very rough, which makes the attachment of its periosteal membrane the more firmly ad- herent. Large grooves for the protection of the larger blood- vessels, the nerves and the absorbents, as well as holes for their passage into the interior of the bone may be seen upon its lateral surfaces. Its posterior aspect exhibits two surfaces for articulating with the coronal and navicular bones. The prolongations of the bone backward on either side are called the alse or wings of this bone. The inferior, or plantar surface, is comparatively smooth and concave, and its general outline corresponds with that of the 31 horny sole, having a deep indentation which affords space for the repose of the principal cushion, or the thickest portion of the plantar cushion of the foot. In view of the functions this bone is destined to fulfill in the animal economy, it may be instructive to note some of its more salient properties. " A MOCKERY, A DELUSION, AND A SNARE." I. The extreme lightness of this bone in comparison to its bulk is remarkable. This is rendered necessary by its great distance from the moving power. It is said that every addi- tional ounce added to the foot is nearly if not more than equal to a pound at the shoulder. If, therefore, we would economize the vital forces, no more weight should be placed at the end of the foot than is absolutely necessary to insure protection to the integrity of the horny tissues in horses intended for speed. Concussion, the ready apology for heavy shoes, can be better obviated by a ' stout sole ' of horn than by a heavy rim of iron. If concussion were the only danger to be guarded against, this could be accomplished better without the intervention of the shoe than with it. I grant that the horse with a thin sole and weak foot generally, and low action, will go better at relatively slow paces, with a comparatively heavy shoe. It does obviate concussion to some extent, and to that extent and under those conditions it is desirable ; but reverse those conditions, place heavy shoes upon a sound foot, with unimpaired action, and a well-developed horny sole and frog, and they become " a mock- ery, a delusion, and a snare " to both the horse and his owner. These objections to heavy shoes do not apply to the trainers practice of using toe-weights for the purpose of regulating or correcting defective action in trotting horses. In such cases, as well as in diseased conditions, any and every measure that will accomplish the desired purpose, are, of course, proper. They are useful as temporary expedients but should not be regarded as permanent natural or necessary conditions. 32 THE PEDESTAL OF THE COLUMN. 2. It is the last bone of the series, which compose the sup- porting structures of the limb ; the pedestal of the column that carries the superstructure. It therefore spreads out in accord- ance with the principle of mechanics which requires a sup- porting base of wider proportions than the shaft it sustains, in order to give stability to the vertical position. A REMARKABLY CONSTRUCTED BONE. 3. This bone is constructed upon the plan of a double arch. It is a well known physical law that the arched form affords the greater degree of strength with the least weight. The arched form of the sole resembles the concaved surface of a dished wheel with its concave surface facing the ground. The archiform parieties of the bone are the best calculated to resist forces acting against it in various directions from which dangers may come, and combines the lightness neces- sary for speed with the strength essential to endurance, and protection to the exceedingly delicate structures and processes within it. ESSENTIAL IMPORTANCE OF THE FOOT. The safety of the horse in his natural state, depending more upon his capabilities for flight than upon the resources of strat- agem, this bone appears to have been designed primarily for that object, " No foot, no horse," seems to have been the motto of its Designer. Double walls enguard the brain from external accidents. Arched ribs enclose and shield the heart and lungs from many outward casualties. Scarcely less inferior in im- portance to the safety of the animal, is the organ of Right par excellence^ and that is endowed with a doubly vaulted bone» that receives within the protecting aegis of its recesses a won- derful assemblage of arteries, capillaries, veins, nerves, and absorbents from whence they emerge in various directions to play the part assigned them in the general economy. 33 THE OS CORONA. This bone belongs to the class of long bones. It possesses the peculiarities of having no medullary canal, and of being more broad than long. In a horse of medium size it is about an inch and a half in length, and two inches in width. Its general form is cuboid. It articulates superiorly with the os suffraginis or large pastern bone ; inferiorly with the os pedis and navicular bone. Its anterior surface is rounded, its pos- terior, flattened. It lies partly within and partly without the hoof. The tendon of the Flexor Pedis Perforatus is inserted into its upper posterior border, and a little below its insertion is a transverse flattened eminence covered by fibro-cartilage which forms a gliding surface for the tendon of the Perforans.j In blocky, upright feet, this bone is peculiarly subject to the bone -affection known as Ring-bone. It is so short and firmly braced to its position that it rarely becomes dislocated, but is not quite so rarely the subject of fracture. OS NAVICULARE. SYNONYMS — Navicular Bone — Shuttle Bone. This bone in its natural position, lies transversely between the wings of the coffln-bone. It averages about two inches in length ; half an inch in breadth ; and three eighths of an inch at its thickest part. It has three surfaces of articulation, the smallest with the coffin bone, the largest with the perforans tendon and the medial sized one with the small pastern. It is held in position by remarkably strong ligaments, and are respectively named the interosseus ligament uniting it inferiorly with the coffin bone; two anterior, and two postero-lateral, that unite it with the small pastern. Besides these, from either end of the bone proceed three ligaments. As they radiate from the end of the bone as from a central point, they are called the Stellate ligaments. The insertions of these ligaments embrace about half a circle,, the middle ligament going straight from the end of the bone 34 to the highest part of the lateral cartilage, the anterior and posterior stellates going respectively to the most anterior and the most posterior edge of the same cartilages. STELLATE LIGAMENTS AND THEIR USES. Let us philosophize a moment upon the function of these stellate ligaments. A familiar illustration of their use, I think, may be found in the Stay-straps we see under the bodies of coaches and other vehicles, provided with springs, and intended to be driven at rapid rates, and over rough roads. Their use is, perhaps, too obvious to need description. A sailor would call them guy-ropes. To my view, these stellate ligaments have a similar function. They materially assist in keeping the fulcrum, that is, the navicular bone, of the main cord that flexes the foot in exact apposition to the gliding surface of that cord ; otherwise, rapid motion would be retarded. From whichever direction the disturbing force might proceed, there is a species oi guy -rope arrangement to resist it. This is not their only func- tion. Under extraordinary exertion the frog-structures may condense too forcibly and rebound too strongly to be altogether free from danger. They then possess a regulative function. More, under or- dinary circumstances, when there is no excessive action to control, they form powerful auxiliaries to the spring-like move- ments of the elastic structures. The frog-cushion is the great spring-bed of the foot. The lateral cartilages, one on each side, constitute a pair of springs, that are called into play through the medium of the stellate ligaments. These latter are strong and unyielding, while the lateral cartilages possess the properties of flexibility and rebounding in the highest de- gree. I think it impossible to conceive, in any organized structure, of means more perfectly adapted to ends than in the structural arrangements of the stellate ligaments. 35 CARTILAGINOUS STRUCTURES OF THE FOOT. These structures include, 1. The Lateral Cartilages. 2. The Inferior Cartilages. 3. The Articular Cartilages. THE LATERAL CARTILAGES. The Lateral Cartilages are the two cartilaginous bodies already referred to as receiving the attachments of the stellate ligaments of the navicular bone. They are situated upon the superior margin of the wings of the coffin bone, and their position as regards the hoof is about equally within as without that structure. Their superior portions can easily be felt and manipulated by the fingers in the living subject, and the ex- tent to which they may have lost their flexibility pretty nearly ascertained. Externally they are convex, internally concave. Membranous expansions connect them with the extensor ten- don and the coronal bone anteriorly. Posteriorly they be- come thinner, and are extended downwards and inwards, imparting roundness and flexibility to the heels, and afl'ord considerable protection to those parts against casualties by their characteristic properties of firmness and resiliency. The portion of these cartilages that lies in apposition to the lamellated structure of the wall has corresponding lamina for connection therewith. From the inferior extremities of these cartilages, supplementary ones extend, which have been named INFERIOR CARTILAGES and False Cartilages. Mr. Spooner thus describes them: ** They are triangular bodies, and somewhat different in struc- ture from the lateral cartilages. They proceed from the lateral cartilages (just as the latter reach the heels of the coffin-bone) in an obliquely forward direction, on the internal and inferior parts of the wings of that bone, and thus afford a smooth sur- face, which is covered partly by the sensible laminae, and partly by the sensible sole. The inferior are much more fibrous in their structure than the lateral cartilages, and the latter become 36 less cartilaginous toward their upper and posterior part." If the structure of a tissue is any indication of its function, as I believe it will be found to be, then the function of the inferior cartilages is not precisely that of the lateral cartilages, for we find the former much more fibrous in character than the latter; and it is remarkable that the lateral cartilages themselves pos- sess a fibrous border where the stellate ligaments are inserted, and posteriorly where it is connected with the inferior cartil- ages it assumes a more fibrous character generally. The infer- ence is irresistable, drawn from the structure of these cartilages alone, that the lateral cartilages fulfill the office of a pair of side springs, having the property of yielding and rebounding with every motion of the foot, and aiding and regulating in some measure the vertical movements of the elastic tissues of the frog, through the medium of the stellate ligaments superiorly, while inferiorly it is kept in position, aided, and undue move- ments controlled by the strong and comparatively unyielding character of the inferior cartilages. The lateral cartilages are subject to ossification, that is to say, of becoming converted partially or wholly into bone. En- largements are not unfrequently met with, of one or both car- tilages. These are not necessarily ossifications, but they are evidences of a derangement of structure and function, the causes of which will be discussed further on. The lateral and inferior cartilages are covered by a dense tough membrane called the perichondrium, which performs a similar office for cartilaginous to that of the periosteum for osseous structures. ARTICULAR CARTILAGE. This is sometimes referred to as cartilage of encrustation, because this particular kind is only to be found encrusting or adhering to the articular surfaces of bones. As some theorists on the pathology of navicularthritis deem this disease to have its origin, as a rule^ in the disorganization of this structure it may not be uninstructive to learn somewhat of its nature and uses. 37 BUFFERS AND GLIDING SURFACES. Bones are the solid frame-work of the whole body and pos- sess but little elasticity. These supporting and moving structures being also in sec- tions and destined to move freely upon the ends of each other, would have been peculiarly liable to concussion, and their moving surfaces susceptible to attrition but for the interven- tion of a substance of such a nature that would fully meet both requirements. Such a substance we have in articular cartilage. It combines those properties in the most eminent degree, that break the violence of concussion, and by its extremely smooth and glass-like surface, with the aid of the synovial fluid as a lubricator enables the moving surfaces to glide on each other with the greatest facility. Its anti-concussive functions may be likened to those of the buffers upon the different sections of a railway train ; while its free-gliding purposes may be fitly illustrated by those of the smooth portions of the axle trees upon which the train moves. ARTICULAR CARTILAGE; REMARKABLE CHARACTERISTICS. It is remarkable too, that no nerves or blood-vessels are found in articular cartilage, while they are found in all other kinds of cartilage. Why is this ? Because it would be incom- patible with the exercise of its functions if it possessed either sensibility or vascularity. In the former case, every jar or quick movement would be necessarily attended by pain ; and in the latter the vessels would be liable to rupture and extra- vasation of their contents, when the weight of the animal was thrown upon these structures. As nutrition and decay are necessary and constant processes, the nutrient blood-vessels that supply these cartilages approach them as closely as possible at their biise from the interior of the bone to which they belong, not terminating in the cartilage, but abutting against their base by large numbers of small loops, the cartilage having the property of imbibing their nutrient particles from mere contact with the circular terminations of 38 these vascular loops, by the process called cell-imbibition. The cells at first are round, but gradually acquire a flattened form, until, at the wearing surface they become very dense and horn-like in texture. Like as in the hoof and epidermic struct- tures, the outlying particles are being continually pressed upon toward the external surface, and pass off in the processes of wear or natural decay. In such a case absorbents are unne- cessary and therefore none are present. The due secretion of the synovial fluid is necessary to keep the gliding surfaces of these cartilages moist, a condition necessary to the perfect fulfillment of their office in the general organization. In chronic disease of the navicular joint, it has been ocasion- ally found that these cartilages have become abraded from attrition, and in some instances the cartilaginous covering of the navicular bone has been found adhering to the perforans tendon, of which that bone is the fulcrum in its action upon the coffin-bone. A KNOTTY QUESTION. Scarcely any question in the whole range of veterinary path- ological inquiry has excited so much animated discussion and such contrariety of opinion as that of the proximate cause or causes of the navicular-joint disease. Few, even amongst the ablest veterinary pathologists recognize more than one general proximate cause for this foot affection ; and there is not a tissue entering into the composition of the joint, which has not its advocates for its claims to consideratidn as the chief tissue in- volved in this complaint. Some view it as proceeding exclu- sively from internal and other from external causes. The bones, the cartilages, the synovia or its secreting membrane, the perforans tendon, hereditary predisposition, mal-nutrition, atrophy, concussion, etc., all have their separate claims put forward by one writer after another for the bad pre-eminence of being the chief proximate cause of this equine curse. But I must not digress too far from the main course of my subject or anticipate my own theory too soon. To be able satisfac- torily to dispose of conflicting hypotheses, it is important that 39 we should thoroughly understand the nature and uses of every tissue that compose the foot. The articular cartilages are sub- ject to abrasion from a lack of synovia ; to ossification from perverted nutrition ; to ulceration from its propinquity to the ulcerative process in the bone when present, and to adhesion to the perforans tendon, when the latter is the subject of in- flammation which is followed by a lymphy exudation. THE LIGAMENTOUS TEXTURES OF THE FOOT. These textures comprise : 1. The coronary ligament. 2. The periosteum and endosteum of bones. 3. The tendons and tendinous expansions of muscles. 4. The perichondrial membranes. 5. The synovial membranes. 6. The ligaments that brace joints. 7. The areolar or connective tissues. THE CORONARY LIGAMENT. Sui getieris amongst ligamentous textures is the coronary lig- ament. It is variously designated as the coronary ligament, band, or substance. I presume there has been some difficulty^ from the peculiarity of its structure, in defining its true place in the category of foot-textures. As it is most frequently re- ferred to as the coronary ligament, I have placed it under the head of ligamentous textures, with the above remark as to its anomalous classification. n:^. IFUNCTIONS OF THE CORONARY LIGAMENT. The locale of this ligament is the coronary concavity, just inside of the superior margin of the wall. It is the principal medium of connection between the skin and the hoof. It appears to be transitional in its character, partaking somewhat of the characters of both. Its surface towards the wall is papil* lated, and each papilla penetrates a horn tube, or fibre, of which the fibrous portion of the wall is made up. It is affirmed by one writer, Mr. Fleming, that the entire wall is secreted by 40 this ligament. This, of course, would include the horny lam- inae. I dissent from this opinion for the following reasons : The wall is composed of two kinds of material, the fibrous, and a non-fibrous matrix, which bind the fibres firmly into the solid mass of horn which constitutes the wall of the foot. I am not aware of any secreting structure that secretes more than one specific secretion in a healthy acting condition. But if there should be, it would not be a sufficient reason for attributing the functions of secreting two such widely different substances as compose the walls, to the coronary secreting lig- ament. Each fibre of the wall is fed by its connecting papilla. Besides, we are not left in doubt as to where the matrix comes from. I think that is just as demonstrable as the source of the horny fibres. The vascular laminae have not a merely me- chanical connection with the non-vascular horny laminae — but a secreting function, and it is from this source that the homo- geneous or non-fibrous portion of the wall is derived. If an experimental proof of this Is demanded, examples are numerous enough in cases of False-Quarter, and those cases where the hoof has been torn off by violence and the coronary ligament partially or wholly destroyed. In False-Quarter, for instance, the coronary ligament is injured or destroyed, and we have but a thin non-fibrous horny secretion composing the quarters, frequently too weak to sustain the weight of the animal, which could come from no other source ihan the vascular laminae. REASONS VERSUS IPSE DIXITS. In cases where the entire hoof has been torn off while the vascular laminae remain otherwise uninjured, a non-fibrous horny material will be deposited all over the sensitive laminae in a few weeks. Does this come from the coronary ligament.? It can not, as ten or twelve months will scarcely suffice for the growth of horn from the top to the bottom of the foot. I think these experimental facts too well known to need any further exemplification. Mr. Fleming, in his recent work on Practical Horse-shoeing, asserts that the latter view is an error, " as the microscope, physiology, and pathological experience, 41 abundantly testify." This is all the refutation he has con- descended to give to this alleged error. Supposing it to be an error; it can hardly be expected, that those who are accus- tomed to do their own thinking, to weigh the opinions of others for themselves, and to rely on their own pathological experience, when they have any, will readily abandon their opinions with- out a single reason being advanced or a particle of evidence adduced to show that they are erroneous, beyond the mere ipse dixit of any writer, however eminent he may be as an authority in some respects. I repeat, the principal function of the coronary ligament is to secrete the fibrous portion of the wall. It is extremely vascular and highly elastic. The for- mer quality is necessary to supply the demands of rapid wear and tear to which the wall is subject especially in the unshod foot, and to maintain the integrity of the structure it secretes ; the latter to adapt it to the expansive and contractile move- ments of the foot when in action, or when weight is super- imposed upon, or removed from the limb. Although in appear- ance a thickening of the terminal portion of the skin, it has a peculiar and distinct organization to adapt it to its very im- portant purposes. The inner layer is a strong white elastic structure which forms its principal thickness. Upon this reposes a very numerous accumulation of blood-vessels, and external to these a thin coat from which proceed the secreting villi of the wall. The attachments of these villi in the living structure must be of a very powerful nature, as there is no other visible connection between the hoof and the skin except the areolar or connective tissue, which bind it but in no very €special manner to all the subjacent structures. The growth of the wall is in every respect similar to the growth of the human nail. THE PERIOSTEAL AND ENDOSTEAL MEMBRANES. These structures are the dense white-fibrous and non-elastic membranes, the former of which constitutes the external cover- ing, and the latter' the internal lining of bones. They are 42 connected by prolongations of their substance through small conduits in the bone called the Haversian canals. Their func- tion is to give support to the bone within and without, and to furnish a bed whereon the nerves, blood-vessels, and absorbents can ramify. Bones are most amply supplied with nutrient materials by these means, and their disintegrated particles probably carried away by the absorbents. I say, probably, be- cause some physiologists consider it doubtful, at least, whether absorbent vessels exist in bone. The coronal and navicular bones present nothing exceptional as regards their periosteal coverings, but there is a very remarkable peculiarity concern- ing the periosteum of the coffin-bone which I think throws much light upon the constitution and functions of the sensitive laminae, a just appreciation of which has a most important bearing upon the question of shoeing, either in health or disease. Microscopic " anatomy, physiology, and pathological experience," perfectly harmonize in the views I have taken upon this master question of the foot, and the practical meas- ures I have based upon them. THE SENSITIVE LAMINA. Mr. Spooner says : " The sensitive laminae are somewhat similar in appearance, but very different in structure to the horny laminae, with which they are connected by a dove-tailed union, each horny plate being received between two sensible plates, and vice versa. They are firmly attached by means of elastic (.?) membranous structure to the irregular surface of the os pedis ; and are also continued on the lower position of the side car- tilages, where they correspond to the horny laminae, on the inside of the bars of the foot. The sensitive laminae, as their name imports, are extremely sensitive and vascular, and as Mr. Percival says, are composed of a double transparent membrane^ plaited as it were around the bone, so that one of the sides of each laminae is in close contact with another, and the other side opposed to a horny lamina. The sensible laminae used to be considered as highly elastic, and writer after writer having 43 copied from each other, without examining for themselves, the error was perpetuated until Mr. Percival demonstrated that the elasticity was not inherent in the laminae but in the sub- stance connecting them with the coffin-bone which possesses highly elastic properties, and affords a convenient bed for the numerous blood-vessels which secrete the laminae." AN UNDETERMINED QUESTION. In this connection the late Prof. Spooner, in the course of his lectures, stated substantially as follows : " The precise nature of the union between the vascular and horny laminae is not yet established. I believe it will be found upon more extended microscopic investigation to be similar to, if not iden- tical with that of the chorion of the foetus, and the tunica decidua uteri of the uterus. The same kind of union also exists between the dermis and epidermis. Whatever doubts may exist as to the histological character of this union, what is certainly known is that the union is a vascular and vital, not a mechanical one, and that it is one of extreme delicacy, and ill-calculated to bear the tremendous burden the weight of the animal would impose upon it." THE INTERPERIOSTEAL PAD. It will not be difficult to perceive where this apparent power of elongation comes from, when the peculiar structure of the periosteum of the coffin-bone is fully comprehended. As shown by Percival it is a double membrane, the union of which is attached to the irregular surface of the coffin bone, and the outer presents a plaited or frilled surface. Between this inner and outer membrane, a layer of elastic material is interposed^ which, like most other structures of the foot, answers a two- fold purpose. It furnishes a nidus or bed for the safe repose of the vessels and nerves that ramify upon the laminae, and particularly those which are engaged in the work of secreting- the horny laminae. The frilled or laminated arrangement affords abundance of space for these vessels and nerves as the>r 44 proceed to the various points of contact and union with the horny laminae, and will yet admit of a certain amount of separ- ation of the outer from the inner portion of the membrane, allowing certain movements of the foot to be effected without any undue strain of the filamentous and vascular connections of the laminae. This elastic material I shall have frequent occasion to allude to again as the interperiosteal tissue, or pad. RELATIVE WEIGHTS SUSTAINED BY FORE AND HIND LIMBS. In further elucidation of the functions of the laminae, quoting Spooner : " Let us consider the vast weight supported by each leg, and the manner in which it is distributed. The weight of a moderate sized horse is about twelve hundred weight ; this, when the animal is standing is supported by the fore and hind legs in the proportion of two-thirds by the former and one- third by the latter. When the horse is in motion, say trotting, this weight is supported alternately by one hind, and one fore leg, so that each fore leg supports two-thirds of the animal's gravity ; to this we must add the weight of the rider, and the increased burden occasioned by the momentum of the horse's action. We shall, therefore, be within bounds when we say that each fore leg alternately bears a weight equal to the ani- mal's entire gravity, all which is borne by the small pastern bone, and is thus distributed to the parts below. A moderate portion is first communicated to the elastic cushion, from whence it is impressed on the lateral and inferior cartilages and posterior part of the frog. The remainder, being the principal portion, is transferred to the navicular and coffin- bones, the former of which, by the interposition of the flexor tendon, bears partly on the frog and partly on the sole ; and the latter by the intervention of the laminae, distributes its weight to the wall throughout its whole circumference, and a very slight portion of it is borne by the sole, which may or may not bear upon the ground. Thus at the same moment 45 these various actions go on in the foot. The coffin bone de- scends lower into the hoof, the laminae, by their elastic connec- tions, permitting it ; the sensible sole is compressed, and perhaps the horny laminae opposite the coffin bone slightly descends. Well, the horny sole and the anterior part of the frog opposite the navicular bone descend and expand the quarters parallel to them, whilst at the same time, the elastic or sensible frog, being compressed, is forced down upon the horny frog, and contri- butes to the expansion of the heels ; but if the horny frog meets the ground, the cushion, being pressed upon both above and be- low, enlarges laterally, and expands the upper part of the foot and lateral cartilages." This quotation is introduced for the purpose of showing the loose views entertained by one of the most influential authori- ties upon the " Foot of the Horse," regarding the most impor- tant function possibly pertaining to that organ, namely, the sus- taining or supporting ordination of the sole. He says the sole " 7nay or may not " have a bearing upon the ground. I affirm that it must have a bearing either upon the ground or its equiv- alent, the shoe, in order to exercise and maintain its functions in a state of efficiency. FACILIS DECENSUS AVERNUS. Descent of the horny sole being regarded as a function, this error renders the acquisition of erroneous views necessary to support it, an easy matter; just as a recognition of its falsity, and the necessity of a supporting function to the sole will have an important influence in producing correct views of other func- tions. It does not, however, always do this, as I shall show by an illustrious example, namely. Professor Gamgee, senior, who, though strenuously advocating a sustaining function to the sole, denies the contractility and expansibility of the foot func- tionally or otherwise ! Per contra, Mr. Spooner recognizes this latter function, but is loose-jointed upon the sustaining func- tions of the sole, ^ow passing strange^ that men of such mark, and of such ^^ large discourse'' upon that ever-fertile topic, the 46 foot of the horse, should differ so diametrically upon matters that appear to be of the most simple and demonstrable char- acter, as I think will be seen when we discuss the other functions of the foot. THE SENSITIVE SOLE, Besides the laminal tissues, the periosteum of the coffin bone furnishes a double membrane from its plantar surface to fulfill similar functions for the horny and sensitive soles. Here, also, proceeding from within outwards, we have the basal membrane adherent to the bone, and a secreting membrane sending its papillae into the internal surface of the horny sole, besides a layer of elastic interperiosteal tissue coming between the two layers of membrane last described — that is to say, it furnishes a bed whereon the nerves, blood-vessels, and absorbents may repose with safety, and yet suffer the necessary elongation and shortening incidental to the movements of the foot without injury ; and, being of the elastic variety of fibrous tissues, forms the appropriate elastic medium, when its functions are unim- peded, by which the natural springing and rebounding func- tions claimed for the plantar cushion, for such it is, are effected. AN ERRONEOUS CONCEPTION EXPOSED. If the above description of the sensitive sole be correct, as I deem it demonstrable that it is, by actual experiment, then the common notion that the horny sole should be cut until it springs or yields under the pressure of the thumb must be founded upon an erroneous conception of the function of the sole, no matter by whomsoever the doctrine may be taught, since this practice neutralizes, to the extent to which it may be followed, the action of the really elastic tissue within the foot, and calls upon tissues that are not elastic to fulfill functions for which they were neither designed nor adapted ; and, more- over, endangers the vascular and filamentous connections of the sensitive and the horny laminae, as well as those of the sensitive and the horny sole, by causing a greater tension upon those connections than they are able, or were intended to bear. 47 MR. FLEMING, RISE AND EXPLAIN. THE "SOLAR ZONE." There is a white line that marks the line of junction of the sole and wall. It is undoubtedly the cementing medium of the two portions of the hoof. In some prior observations on the lami- nae made by Mr. Fleming, it will be remembered that he stated that the " microscope, physiology, and pathological experience abundantly testify that the horny leaves are not formed at all by the sensitive ones, and that the coronary ligament secreted he entire wall." How, then, does it happen that the source of this " softer and more elastic white zone " is ascribed to '*the secreting villi oi the lower end of the sensitive laminae?" If the sensitive laminae have secreting functions at one part, why not at another .? And if not, why not "i If they have not, what need is there of any vascular attachment between the two de- scriptions of laminae, when a merely mechanical one would do as well .^ If a portion of the horny wall is not secreted from its sensitive counterpart, perhaps the horny sole and frog are not secreted by their sensitive counterparts; for the inference in one case is just as reasonable as in all three ; and if they are not, from whence are they derived ? Presuming upon the pos- sibility that Mr. Fleming may alight, in the course of his pro- miscuous reading, upon these questions, I shall be expecting an answer to them in some future edition of his work on " Prac- tical Horse-Shoeing " or in some other way. THE SENSITIVE FROG. This structure presents a double membranous arrangement, -similar in this respect to the secreting organs of the sole and wall. Extensions of a dense white fibrous membrane, almost, if not quite, identical with the periosteal tissues before described, completely invest this substance. Its secreting papillae pene- trate the horny frog, just as those of the sensitive sole are im- bedded into the pores of the corneous sole ; but they are said 48 to be of a finer and more delicate structure than those of the sensitive sole. They also take the same oblique direction downwards and forwards as those of the sensitive sole. View- ing the internal aspect of the hoof, a long, deep, triangular fissure will be seen, with a small eminence springing from its medial line, near the basal end of the triangle. In and over this fissure, and adjacent thereto, the sensitive frog reposes. This sensitive frog may also be regarded as an interperiosteal pad or cushion, only, compared to the others, it is of greatly magnified dimensions. It fills up the whole of the posterior space of the foot not occupied by other substantial tissues. This, the principal spring-cushion of the foot, as to size, is com- posed of two kinds of ligamentous tissue — the white fibrous and the yellow elastic. The mass of the frog-cushion is com- posed of the same material as constitutes the sub-cutaneous tissues, usually designated connective or areolar tissues. To- wards the posterior portion of the foot these tissues are trans- formed into a vast fibro-cartilaginous cushion, otherwise known as the sensitive frog. Its eminently elastic properties are due to its yellow elastic constituent, which predominates most in the upper portion of the pad that lies in close contiguity to the perforans tendon and the inferior portion of the coronal bone. CHARACTERISTIC STRUCTURE OF THE FROG. Another remarkable feature of the constitution of the frog- cushion, which only the microscope could reveal, is the manner in which these fibrous materials of the sensitive frog are dis- posed. There is no apparent order in their disposition, but they are interwoven with each other in every conceivable direc- tion, thus forming a dense areolated mass of tissue. These areolae are exceedingly minute, and it is within these that the yellow elastic fibres called " fiuclear " are discovered to exist. It is this variety of fibre that gives elastic properties to an oth- erwise inelastic substance. The chief characteristic, therefore, of the frog-cushion is firmness, combined with lightness and elasticity, it being endowed with the latter property in every conceivable direction. 49 STRUCTURE INDICATES FUNCTION. These minute particulars as to the structure of the frog- cushion — and they could have been made more minute still — • I deem of importance, as they point unmistakably to its func- tions. " Men do not gather grapes from thorns, nor figs from thistles ; " but they sometimes commit the equally egregious blunder of attributing functions to organs and textures which are altogether foreign to their destined purposes, through im- perfect acquaintance with their intimate composition and organ- ization. These considerations, together with the desire I en- tertain that the sub-structure of my theory and practice in regard to diseases of the feet shall be laid sufficiently broad and deep in the facts of anatomy and physiology must be my apol- ogy, if any were needed, for dwelling so long upon the compo- sition and organization of tissues. FUNCTIONS OF THE FROG. The highly important functions of the frog have yet to be considered. The horny frog is evidently designed to receive pressure externally, as without this there would be no basis afforded for the resilient movements of the internal spring- cushion — that is to say, the sensitive frog. The most familiar illustration of this view is the following: Take the spring- cushion of a carriage, or the spring-mattress of a bed. It will be seen that the spiral spring is fastened by one end to a solid base or frame-work. The full action of the spring is thus ob- tained ; but if the solid base is removed, and a yielding base substituted, the action of the spring is neutralized in proportion to the yielding character of the base ; in other words, much of its resilient action is lost, and the body, sitting or recumbent upon either, would sink to a lower level and find less springi- ness on the seat or the bed. IMPORTANCE OF A HEALTHY FROG. Thus, the sensitive frog is the spring-cushion, and the horny frog its base of action, when these tissues and functions are un- interfered with. 60 The horny frog interposes a firm resisting medium between the sensitive frog and the ground. The sensitive frog com- presses more readily under the double effect of superior and inferior pressure. It thus lets the weight of the animal down easy upon the other portions of the foot, and the instant the weight is removed in the lifting movement, regains its original dimensions. It is to this expansive or rebounding movement that I attribute the regular, light, easy, corky\ springing move- ments in action that is peculiar to the horse. MAXIMUM AND MINIMUM OF LATERAL MOVEMENTS. The sensitive frog and the fissure in which it reposes are also evidently constructed so as to admit of some degree of lateral movement. The peculiar construction, too, of the sensitive frog adapts it, I think, to receive or to resist pressure in every direction, its areolae admitting of the maximum amount of rapid condensation with the minimum of the lateral increase of bulk. SUMMARY OF VIEWS. Summarizing the foregoing views — the superimposed weight of the animal superiorly^ the solid bases afforded by the horny frog inferiorly, the quarters of the horny wall laterally — these are the solid resistants that call the compressive and the expan- sive forces of the frog-cushion into play. More elasticity than that which is inherent in these resisting structures, or any in- terference with the due fulfillment of the functions of any one or more of them, such as contracted quarters and a diseased horny frog, would injure the structure and suspend the func- tions of the primary organ of resiliency, the sensitive frog and proportionately will be the impairment of the leg or knee action of the animal subject to such an abnormal condition of things. The question of the Expansibility of the Foot is too important to be dismissed with a cursory allusion. It will arise for con- sideration in due course, and will then receive the attention it merits. TENDONS AND TENDINOUS TEXTURES. Several varieties of these textures are to be found entering into that complex organism, the foot of the horse. 1. The tendons directly connecting the bones with the muscles that act upon them. 2. The tendinous expansions that envelope joints. 3. The tendinous structures that connect bones that are in close apposition to each other in joint formations. 4. The external lateral ligaments of joints. 5. The stellate ligaments of the navicular bone. GENERAL CHARACTER OF TENDINOUS TEXTURES. All the above structures have the same general composition, differing only in the arrangement of their fibres. The dense, tough, white, tendinous expansions that embrace the joints, and the inelastic silvery ligaments and tendons that form ex- tensions of muscles, are alike of the white fibrous variety of tissues, and are composed of white filaments, similar in every respect to the fibrous areolar tissues. They only differ in the arrangement of their fibres. They are all, however, arranged in a parallel manner, and, being inelastic, give a firm union to those structures with which they are continuous at their ends. Yet, though they are described as inelastic, they are not abso- lutely so, as is shown by the fact that a small number of yellow elastic fibres is interspersed among the bundles of white fibres. This undoubtedly imparts some security against the chances of 52 a rupture, by admitting of a slight degree of elongation under extremely trying circumstances. Histologists give the name of *" nuclear' to these yellow elastic fibres. The tendons and faschiae, or tendinous bands, are bundles of filaments of white fibres. The aponeurotic expansions are also filamentous bun- dles of the same material, strips of which interlace each other, and a quantity of reticular connective tissue giving them a bond of union. It is the toughness and inextensibility of white fibrous tissue that render it so serviceable in attaching muscle to bone, and in connecting bones where they articulate with each other. This tissue is but slightly vascular, and contains fewer blood-vessels in the adult than in the young animal. AN IMPORTANT ANATOMICAL FACT. It is not unimportant to remember that in certain exigencies the division of tendons, faschiae, and ligaments is unattended with pain, so that these structures are devoid of sensibility. There is no tissue more easily reproduced ; and the only con- dition for effectual reunion is, that the divided ends be brought as close together as possible, in order to prevent any increase in the length of the bond of union. Perfect rest of parts is the best means to insure the healing of a cut or torn ligament or tendon. No other means can be adopted to increase the strength of the white fibrous tissue. This is mentioned, be- cause veterinary surgeons still resort to blistering and firing, in the belief that they insure animals from not lacerating liga- ments or tendons a second time. THE FLEXOR TENDONS OF THE FOOT. The most important tendons of the foot are those which have their insertion in the coffin or pedal bone ; the tendon of the Flexor Pedis Perforans, and that of the Extensor Pedis, and that which is inserted into the coronal bone, the tendon of the Flexor Pedis Perforatus. The latter and the former will be alluded to, for the sake of brevity, as the Flexors^ and the other as the Extensor. If we take the Extensor Suffraginis into account^ 53 we shall then have two Flexors and two Extensors. The largest and most powerful of these tendons is that of the Perforans muscle ; the next, that of the perforatus. The two last main- tain a very intimate companionship from their origin to their insertion. They are the two largest of the fore limb. The late Professor Dick's favorite theory concerning the navicular dis- ease was, that "injury to this tendon in the synovial capsule of the navicular joint was most generally the primary and proxi- mate cause." The perforans tendon passes under the navicu- lar bone, and is inserted into the posterior pit of the pedal bone. The navicular bone affords a fulcrum, by which means the flexion of the foot is accomplished more easily than could be