- Email: [email protected]
Lectures on Soundness in Horses
L ectures on Soundness ill H orses.
335
remove these forcibly, as hitherto the granulations appear to have insinuat ed them selves between the dead and li ving bone, and have aided in the work of ex foliation. To my aston ishment, the soles have not bulged much as yet, nor do they appear to be likely t o do so now.
LECTURES ON
SOUND~ESS
BY PROFESSOR FEARNLEY, LATE
IN HORSES,
l'RI;.,'CIPAL AXD PROFESSOR
IN TIlE ROYAL VETERINARY COLLEGE, EDINBURGH. LECTURE
II.
GENTLElIIEN,-At our last meeting you will remember that we had brought the horse out of hi s stall, and having closed the door of the sta bl e, were examining hi s eyes by the lig ht over the door. I mentioned trying the t ension of the two eyes, and shall only further observe that so much is tension resorted to as a test in the s ister profession, that Mr. Bowman, of London, the di stin guish ed oculist, indicates nine degrees of tension. We ought at least to distinguish three degrees: I, norm al; 2; increased; 3, diminished. The anterior h alf of the eye, when apparently sound, or, still more, when evident ly affected, claims our attention, seeing that the t ension t es t and the relative size t est have disposed of the post erior hal f sati sfactorily. I mean by the anterior half of the eye, the conjullctiva, cornea, iris, and th e lens, with its capsule; the aqu eous humour seldo m sufferi ng, so far as we can make out, ind ependently of th e structures I have named. The oblique or .focal zllltllliJtatioll is the readiest and best way of examining the anterior half of th e eye. By its aid we are enabled to exa mine, with g reat minuteness, the appearances presented by th e corn ea, iris, pupil, lens, and eve n the most anterior portion of the vi treous humour. A candle or small lamp, and an ordi nary pocket lens of from two-and-a-half to four-inch focu s, is all we require. The light is held in front and to one side of th e eye, at a dist a nc e of about a foot to eighteen inches, and on a level with the eye; the flame is then brought to a focus with the lens, and thrown first on the cornea, then on the iris and crys-
The Velcn'l lary Jourllal . tallin e lens ; the examiner's ey e, bein g placed 011 the opposite side, in front of th e horse's eye, catches th e rays emanating from the latter. By shiftin g the cone of li ght from one p ortion of the cornea or lens to another, we may rapidly, y et thoroughly , examine its whole expanse, and d etect the slightest opaci ty. Opacities of the corn ea or lens app ear by thi s reflected li ght of a light g rey or whitish colour. The catoptric test is a very useful one ill diagnosing cataract, a nd h ad better be used a long with the oblique illumination. It is conducted as follows :-A lig hted candle or taper is moved before the eye. If the organ be healthy, three im ages of th e light are seen. Two of these images are erect, the third is inverted. The first is an erect image of the light, and is produced by refl ection from the surface of the cornea; th e second is also erect, and is produced by refl ection from the a nterior surface of th e lens; the third is inverted, and is du e to refl ection from the concave posterior surface of the lens. The first two images move in the same direction as the light, the third in the opposite directi on. If the lens becomes opaque, of course the image from the posterior surface is lost, and that from the anterior surface al so soon becomes indistinct. Before proceeding further, let me say, once for all, that this is not a course that admits of any discussion on disease, further than considering those disord ers, and their various degrees of intensity, which are open to doubt as to their rendering a horse unfit for the ordinary requirem ents of work, and therefore unsound. The conjunctiva being more vascular, is less li a ble to permanent change than the cornea, so that we seldom look for alterations in it; but there are passing emergencies, such as Conjunctivitis (co ld in the eye), forei gn bodies, and wounds inflicted with the whip, which prevent our examining either the conjunctiva or the eye. In these cases, time should be a llowed for a cure to b e effected before offering an opinion. If, hO\\'ever, the case cannot wait, then exa mine and give an opinion on the other points of th e horse ; but make yourself clea rly ttnd erstood by your client that you give no opinion whatever as t o the ultimate soundn ess of the affected eye. I have known a piece of wh e~ t
L ectures
OJl
SOl{ "a71css in Ilorses.
337
hu sk purposely introduced under th e upper eyelid of a horse suffering from cataract, for r easo ns too obvious t o mention. The cornea, of all othe r structures of the eye, most frequently sh ows sig ns of previ ous disease; and wh en we allow ample roo m for enlargement of th e pupil in comparative darkn ess, the cornea in fro nt of the pupil so dilated cl a ims our special attention ; for any opaciti es, from whatev e r cau se, are unsoundn esses so lo ng as they may last, and it is fo r llS to det erm in e whe the r th ey are t empo rary or permanent. The deg ree of opac ity with in th i~; area must be entirely set aside, as th ere is no opacity which can be seen by us that will not materially interfere with tbe rays of lig ht, a nd th erefore with vi sion. \Vhen we co llle to rem em ber how frequently the whip is abused, we must b e ca refu l in noti c ill ~ the cornea of the right eye more especially; and since we dl) not find th e pupi l fully dilated, we may safely allow that th e ey e is practically sound if the opac ity is so near th e marg in of th e cornea as the sixth of an inch, and is of long standing-that is, that it is not progressive. S hould any cicatrix from wound or ulcer, no matter on what part of the cornea it occu r, a lter ib convexity, then it is unsoundn ess ; ind eed, you sh ould a lways look at the convexity of th e corn ea:: ; for if conica l or too flat, we h ave not the means of rectifyi ng the ingoing rays by lenses (spectacles) ; therefore such eyes cannot be considered sound. The iris we h ave a lready part ially noticed. Care shou ld b e t aken t o ascertai n whether this important muscle is in propcr t onc. Excluding the light from the eye with b oth th e hand ~ . then sudd enly un coverin g th e eye under exami na t.ion, will determine the amount of tone the iris possesses. It should dimini sh and enlarge the pupil slowly and stead ily, but obvi ously. Sometim es the "corpora nigra" h ang m ore loosely than usual, or they m ay be actually torn. I have known seve ral in stances of hunters falling on th eir heads and displacing these little black b odies. \ Vhe n so displaced, the circumstance is not of importance in itself, but th e blow which caused it may have displaced the lense, or even partially ruptured the capsule of the lens, when- the aqueo us humour being admitted into that bodycatarac t resu lts. This is th e explan ation of catarac t s ud denly formin g aft er a severe fall or blow on the head. VOL. 1.
? ...
-.)
The Veterz"nary Journal. The lens and its capsule next engage our attention. After the co rn ea they are of most importance. Since the use of the ophthalm oscope has b ecome general, the cat optric test is now no longer used by skilful surgeons in exam ining the lens, the obliqu e illumination a nd th e mirror of the ophthalmoscop e havi ng quite displaced it. Although you may n ot be able to use an oph thalmoscope in its entirety, still you ought t o carry on e. The lens you use for oblique illumination, and the mirror part, with a lig ht, can be e mployed by the most unprac ti sed; so much so, that frequently when I h ave bee n asked rega rding th e cause of "shyin g," and on exa mining the horse's lens with a li ght ed candle and the mirror part of the ophtha lmoscop e, h ave fOllnd the most mi nute sp eck of cataract, I have delighted the owner by a llowing him to see th at which has b een the cause of the shy in g in this way. To use a n ophthalmosco pe effi.cie ntly, r equires a lm ost as much practice as it does t o play the pianoforte, it being the most difficult t o use of any in strum ent in th e wh ole of surge ry, not ex cludin g th e lithotrite ; but anyone may use th e mirro r part at once. Wh en do ing so, a ny opac iti es of th e cornea or lens appear as dark spots upon a . bright red backg round. I n eed· hard ly say that any trace of opacity in e ith er th e lens or its capsule is an unsoundn ess which ca n not be passed over. Havin g go t so far, a nd th e eyes being found a ll rig ht, we next brin g the horse out of th e stable, and, wh e n possible, place him on level g round. D urin g the nex t man re uvre-that of walki ng round th e h orse, a nd t aking a general vi ew of him-we h ave often t o find fault with d ealers' men for h old ing th e animal with th e head up, in stead of th eir t ak ing a long hold of the bridle or halter, a nd allowing the horse t o have hi s h ead free. This is rea ll y importa nt, for a t this st age it often happens that we find ble mi shes wh ich would rend er it unnecessary to continue the ex amination; some of which blemishes may be concea led by the tri ck of holding up the head and fri ghtenin g th e h orse into the att itud e of "attenti on." In goin g round the horse at this st age, a practised eye soon fi nds a spavin, a fractu red ileum, odd eyes, odd fore feet, and so many oth er thin gs, that it is of import ance t o do thi s carefully, as we may frequen tl y cut short the exa mina-
L ectures on Soulldness £n Horses.
339
tion. Of the tb ousand-and-one blemishes, one or more of which we may now perceive, I have nothing to say at present; but it is at thi s stage one sees" shaky" fore legs, with or \\·ithout broken kn ees. \ Vith regard to broken kn ees, \I·e can dispose of the case qui ckly and without a second th ough t; but if, as often happens, we come ac ross th em when in oth er respects they are perfect, we frequently fi nd a difficulty in decid ing. I may h ere t ell you that this trembling condition of th e fore legs is due t o a loss of b alance in the t one of th e extenso r a nd fl exor muscles of the leg; this Ill ay be congenital, or be brought a bou t by overwork, or, sudde nly, by ove r-exerti on. In so me cases, this loss of balance betl\'een the t\\·o oppos ing sets of muscles is sufficient to th row t he knees forward , and g ive the fore legs a permanent bend. I have no d oubt you will a ll have seen such cases in h orses of unbl emish ed reputation as hunte rs and as ha rness horses ; but in these cases safety of the "forehand" is ensured by th e limbs accommodatin g the mselves to the altered circumstances. Almost at any cover-sid e you may observe this bent condition of the fore limbs. I have frequently seen hunte rs carrying h eavy weight s while labourin g un der thi s, at all times, unfavourable condition; but when it 111;ty b e loo k ed upon as safe, the n eck :1. nd should ers arc fine, th e latt er a re "well b ack," a nd the legs thrown forwa rd. In not a few of these cases you may learn that th e h orse has been so fro m t be t im e h e was a foal. Without signs of broken knees, you will be un able, and mostly unwill ing, t o condemn such as un sound. \Vh en, however, you find shaky legs, a nd upright clumsy should ers, with o r without a h eavy "forehand," an d witbout broke n knees, you will have litt le hesitati on in condemnin g the horse. A t our n ext m eeting we will bc~ in to review the second stage of the examination. ( J~
(" . cOlllillll<"ll.)
335
remove these forcibly, as hitherto the granulations appear to have insinuat ed them selves between the dead and li ving bone, and have aided in the work of ex foliation. To my aston ishment, the soles have not bulged much as yet, nor do they appear to be likely t o do so now.
LECTURES ON
SOUND~ESS
BY PROFESSOR FEARNLEY, LATE
IN HORSES,
l'RI;.,'CIPAL AXD PROFESSOR
IN TIlE ROYAL VETERINARY COLLEGE, EDINBURGH. LECTURE
II.
GENTLElIIEN,-At our last meeting you will remember that we had brought the horse out of hi s stall, and having closed the door of the sta bl e, were examining hi s eyes by the lig ht over the door. I mentioned trying the t ension of the two eyes, and shall only further observe that so much is tension resorted to as a test in the s ister profession, that Mr. Bowman, of London, the di stin guish ed oculist, indicates nine degrees of tension. We ought at least to distinguish three degrees: I, norm al; 2; increased; 3, diminished. The anterior h alf of the eye, when apparently sound, or, still more, when evident ly affected, claims our attention, seeing that the t ension t es t and the relative size t est have disposed of the post erior hal f sati sfactorily. I mean by the anterior half of the eye, the conjullctiva, cornea, iris, and th e lens, with its capsule; the aqu eous humour seldo m sufferi ng, so far as we can make out, ind ependently of th e structures I have named. The oblique or .focal zllltllliJtatioll is the readiest and best way of examining the anterior half of th e eye. By its aid we are enabled to exa mine, with g reat minuteness, the appearances presented by th e corn ea, iris, pupil, lens, and eve n the most anterior portion of the vi treous humour. A candle or small lamp, and an ordi nary pocket lens of from two-and-a-half to four-inch focu s, is all we require. The light is held in front and to one side of th e eye, at a dist a nc e of about a foot to eighteen inches, and on a level with the eye; the flame is then brought to a focus with the lens, and thrown first on the cornea, then on the iris and crys-
The Velcn'l lary Jourllal . tallin e lens ; the examiner's ey e, bein g placed 011 the opposite side, in front of th e horse's eye, catches th e rays emanating from the latter. By shiftin g the cone of li ght from one p ortion of the cornea or lens to another, we may rapidly, y et thoroughly , examine its whole expanse, and d etect the slightest opaci ty. Opacities of the corn ea or lens app ear by thi s reflected li ght of a light g rey or whitish colour. The catoptric test is a very useful one ill diagnosing cataract, a nd h ad better be used a long with the oblique illumination. It is conducted as follows :-A lig hted candle or taper is moved before the eye. If the organ be healthy, three im ages of th e light are seen. Two of these images are erect, the third is inverted. The first is an erect image of the light, and is produced by refl ection from the surface of the cornea; th e second is also erect, and is produced by refl ection from the a nterior surface of th e lens; the third is inverted, and is du e to refl ection from the concave posterior surface of the lens. The first two images move in the same direction as the light, the third in the opposite directi on. If the lens becomes opaque, of course the image from the posterior surface is lost, and that from the anterior surface al so soon becomes indistinct. Before proceeding further, let me say, once for all, that this is not a course that admits of any discussion on disease, further than considering those disord ers, and their various degrees of intensity, which are open to doubt as to their rendering a horse unfit for the ordinary requirem ents of work, and therefore unsound. The conjunctiva being more vascular, is less li a ble to permanent change than the cornea, so that we seldom look for alterations in it; but there are passing emergencies, such as Conjunctivitis (co ld in the eye), forei gn bodies, and wounds inflicted with the whip, which prevent our examining either the conjunctiva or the eye. In these cases, time should be a llowed for a cure to b e effected before offering an opinion. If, hO\\'ever, the case cannot wait, then exa mine and give an opinion on the other points of th e horse ; but make yourself clea rly ttnd erstood by your client that you give no opinion whatever as t o the ultimate soundn ess of the affected eye. I have known a piece of wh e~ t
L ectures
OJl
SOl{ "a71css in Ilorses.
337
hu sk purposely introduced under th e upper eyelid of a horse suffering from cataract, for r easo ns too obvious t o mention. The cornea, of all othe r structures of the eye, most frequently sh ows sig ns of previ ous disease; and wh en we allow ample roo m for enlargement of th e pupil in comparative darkn ess, the cornea in fro nt of the pupil so dilated cl a ims our special attention ; for any opaciti es, from whatev e r cau se, are unsoundn esses so lo ng as they may last, and it is fo r llS to det erm in e whe the r th ey are t empo rary or permanent. The deg ree of opac ity with in th i~; area must be entirely set aside, as th ere is no opacity which can be seen by us that will not materially interfere with tbe rays of lig ht, a nd th erefore with vi sion. \Vhen we co llle to rem em ber how frequently the whip is abused, we must b e ca refu l in noti c ill ~ the cornea of the right eye more especially; and since we dl) not find th e pupi l fully dilated, we may safely allow that th e ey e is practically sound if the opac ity is so near th e marg in of th e cornea as the sixth of an inch, and is of long standing-that is, that it is not progressive. S hould any cicatrix from wound or ulcer, no matter on what part of the cornea it occu r, a lter ib convexity, then it is unsoundn ess ; ind eed, you sh ould a lways look at the convexity of th e corn ea:: ; for if conica l or too flat, we h ave not the means of rectifyi ng the ingoing rays by lenses (spectacles) ; therefore such eyes cannot be considered sound. The iris we h ave a lready part ially noticed. Care shou ld b e t aken t o ascertai n whether this important muscle is in propcr t onc. Excluding the light from the eye with b oth th e hand ~ . then sudd enly un coverin g th e eye under exami na t.ion, will determine the amount of tone the iris possesses. It should dimini sh and enlarge the pupil slowly and stead ily, but obvi ously. Sometim es the "corpora nigra" h ang m ore loosely than usual, or they m ay be actually torn. I have known seve ral in stances of hunters falling on th eir heads and displacing these little black b odies. \ Vhe n so displaced, the circumstance is not of importance in itself, but th e blow which caused it may have displaced the lense, or even partially ruptured the capsule of the lens, when- the aqueo us humour being admitted into that bodycatarac t resu lts. This is th e explan ation of catarac t s ud denly formin g aft er a severe fall or blow on the head. VOL. 1.
? ...
-.)
The Veterz"nary Journal. The lens and its capsule next engage our attention. After the co rn ea they are of most importance. Since the use of the ophthalm oscope has b ecome general, the cat optric test is now no longer used by skilful surgeons in exam ining the lens, the obliqu e illumination a nd th e mirror of the ophthalmoscop e havi ng quite displaced it. Although you may n ot be able to use an oph thalmoscope in its entirety, still you ought t o carry on e. The lens you use for oblique illumination, and the mirror part, with a lig ht, can be e mployed by the most unprac ti sed; so much so, that frequently when I h ave bee n asked rega rding th e cause of "shyin g," and on exa mining the horse's lens with a li ght ed candle and the mirror part of the ophtha lmoscop e, h ave fOllnd the most mi nute sp eck of cataract, I have delighted the owner by a llowing him to see th at which has b een the cause of the shy in g in this way. To use a n ophthalmosco pe effi.cie ntly, r equires a lm ost as much practice as it does t o play the pianoforte, it being the most difficult t o use of any in strum ent in th e wh ole of surge ry, not ex cludin g th e lithotrite ; but anyone may use th e mirro r part at once. Wh en do ing so, a ny opac iti es of th e cornea or lens appear as dark spots upon a . bright red backg round. I n eed· hard ly say that any trace of opacity in e ith er th e lens or its capsule is an unsoundn ess which ca n not be passed over. Havin g go t so far, a nd th e eyes being found a ll rig ht, we next brin g the horse out of th e stable, and, wh e n possible, place him on level g round. D urin g the nex t man re uvre-that of walki ng round th e h orse, a nd t aking a general vi ew of him-we h ave often t o find fault with d ealers' men for h old ing th e animal with th e head up, in stead of th eir t ak ing a long hold of the bridle or halter, a nd allowing the horse t o have hi s h ead free. This is rea ll y importa nt, for a t this st age it often happens that we find ble mi shes wh ich would rend er it unnecessary to continue the ex amination; some of which blemishes may be concea led by the tri ck of holding up the head and fri ghtenin g th e h orse into the att itud e of "attenti on." In goin g round the horse at this st age, a practised eye soon fi nds a spavin, a fractu red ileum, odd eyes, odd fore feet, and so many oth er thin gs, that it is of import ance t o do thi s carefully, as we may frequen tl y cut short the exa mina-
L ectures on Soulldness £n Horses.
339
tion. Of the tb ousand-and-one blemishes, one or more of which we may now perceive, I have nothing to say at present; but it is at thi s stage one sees" shaky" fore legs, with or \\·ithout broken kn ees. \ Vith regard to broken kn ees, \I·e can dispose of the case qui ckly and without a second th ough t; but if, as often happens, we come ac ross th em when in oth er respects they are perfect, we frequently fi nd a difficulty in decid ing. I may h ere t ell you that this trembling condition of th e fore legs is due t o a loss of b alance in the t one of th e extenso r a nd fl exor muscles of the leg; this Ill ay be congenital, or be brought a bou t by overwork, or, sudde nly, by ove r-exerti on. In so me cases, this loss of balance betl\'een the t\\·o oppos ing sets of muscles is sufficient to th row t he knees forward , and g ive the fore legs a permanent bend. I have no d oubt you will a ll have seen such cases in h orses of unbl emish ed reputation as hunte rs and as ha rness horses ; but in these cases safety of the "forehand" is ensured by th e limbs accommodatin g the mselves to the altered circumstances. Almost at any cover-sid e you may observe this bent condition of the fore limbs. I have frequently seen hunte rs carrying h eavy weight s while labourin g un der thi s, at all times, unfavourable condition; but when it 111;ty b e loo k ed upon as safe, the n eck :1. nd should ers arc fine, th e latt er a re "well b ack," a nd the legs thrown forwa rd. In not a few of these cases you may learn that th e h orse has been so fro m t be t im e h e was a foal. Without signs of broken knees, you will be un able, and mostly unwill ing, t o condemn such as un sound. \Vh en, however, you find shaky legs, a nd upright clumsy should ers, with o r without a h eavy "forehand," an d witbout broke n knees, you will have litt le hesitati on in condemnin g the horse. A t our n ext m eeting we will bc~ in to review the second stage of the examination. ( J~
(" . cOlllillll<"ll.)