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Canker of the Horse's Foot and Grease

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ABSTRACTS AND REPORTS. of the smears, however, no leucocytosis was observed, nor was any marked inclusion of bacilli or spores in the white corpuscles discovered. Only an odd bacillus was found in the body of a white corpuscle, the majority lying free between the cells. The experiments show, in opposition to the conclusions of Koch, Lamer, Gaffky, and Feser, that even enormous quantities of spores may be fed to fowls and pigeons without effect, but that it is possible to produce anthrax if luge quantities of spores be used and conditions are favourable. The Practical Effect of these Results.--Anthrax very seldom occurs under natural circumstances in birds, although opportunities for infection are great. For the production of infection large quantities of anthrax material must be taken, and also the circumstances must be favourable, such as disease, inanition, and immaturity. Under ordinary conditions anthrax in birds occurs as an acute general disturbance, and is sometimes apoplectiform. The rapidly produced pathological changes seen in the experimental animals are rarely or never seen under natural circumstances. An animal would rarely get so large a quantity of spores. Under natural conditions, however, infection by the ingestion of anthrax flesh, which as is well known rapidly putrefies, and other infected materials, might be favoured by the decomposition products contained in them. The rare occurrence of natural anthrax in birds is not opposed to the high percentage of fatal cases in the experiments, when one considers the favour- able moments chosen for infection and the large quantity of sporulating material used. Under favourable circumstances anthrax may occur naturally in but it is only in the rarest of cases that the bacilli can be demonstrated. In these cases diagnosis must be based on the presence of haomorrhagic enteritis with more or less swelling of the organs, and upon tbe possibility tbat anthrax material may have been eaten in large quantities. (Hofherr, Centralbl. f. Bakt., Parasit. und Infektions., Bd. 55, Heft 6, 6th September 1910, PP·434- 463.) CANKER OF THE HORSE'S FOOT AND GREASE. DEALING with canker first, tbe author reviews the literature on the subject and points out that comparatively little has been written regarding the histological alterations that occur in cases of canker. During the last four years about forty cases have come under his notice, and about twelve of these have been submitted to microscopical examination. His material was derived from animals that underwent operatiom, or from incurable cases that were destroyed. Pieces of diseased horn, with tbe epidermis attached, were fixed in 4 per cent. formalin-alcohol solution, and after hardening in alcobol of increasing strength they were prepared for embedding in paraffin and celloidin. In a few cases the paraffin method was found to be unsuitable on account of the hardness or brittleness of the material. Tbe method of staining that was principally employed was the haomatein and eosin method, methyl eosin being substituted in many cases for the ordinary solution. Gram's method alone, or associated with picrocarmine, safranin, toluidin, sudan, and orange G, was also used, and about 1500 sections were examihed. In the typical cases details of tbe history, clinical symptoms, and treatment were collected. Special attention was paid to the exact description of tbe histological alterations met with. By way of introduction a brief description of tbe normal epithelium of the hoof, with special reference to the staining affinities of certain cells, is given, so tbat the pathological alterations may be better appreciated.
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Page 1: Canker of the Horse's Foot and Grease

ABSTRACTS AND REPORTS.

of the smears, however, no leucocytosis was observed, nor was any marked inclusion of bacilli or spores in the white corpuscles discovered. Only an odd bacillus was found in the body of a white corpuscle, the majority lying free between the cells.

The experiments show, in opposition to the conclusions of Koch, Lamer, Gaffky, and Feser, that even enormous quantities of spores may be fed to fowls and pigeons without effect, but that it is possible to produce anthrax if luge quantities of spores be used and conditions are favourable.

The Practical Effect of these Results.--Anthrax very seldom occurs under natural circumstances in birds, although opportunities for infection are great. For the production of infection large quantities of anthrax material must be taken, and also the circumstances must be favourable, such as disease, inanition, and immaturity. Under ordinary conditions anthrax in birds occurs as an acute general disturbance, and is sometimes apoplectiform.

The rapidly produced pathological changes seen in the experimental animals are rarely or never seen under natural circumstances. An animal would rarely get so large a quantity of spores. Under natural conditions, however, infection by the ingestion of anthrax flesh, which as is well known rapidly putrefies, and other infected materials, might be favoured by the decomposition products contained in them.

The rare occurrence of natural anthrax in birds is not opposed to the high percentage of fatal cases in the experiments, when one considers the favour­able moments chosen for infection and the large quantity of sporulating material used.

Under favourable circumstances anthrax may occur naturally in bird~, but it is only in the rarest of cases that the bacilli can be demonstrated. In these cases diagnosis must be based on the presence of haomorrhagic enteritis with more or less swelling of the organs, and upon tbe possibility tbat anthrax material may have been eaten in large quantities. (Hofherr, Centralbl. f. Bakt., Parasit. und Infektions., Bd. 55, Heft 6, 6th September 1910, PP·434-463.)

CANKER OF THE HORSE'S FOOT AND GREASE.

DEALING with canker first, tbe author reviews the literature on the subject and points out that comparatively little has been written regarding the histological alterations that occur in cases of canker. During the last four years about forty cases have come under his notice, and about twelve of these have been submitted to microscopical examination. His material was derived from animals that underwent operatiom, or from incurable cases that were destroyed. Pieces of diseased horn, with tbe epidermis attached, were fixed in 4 per cent. formalin-alcohol solution, and after hardening in alcobol of increasing strength they were prepared for embedding in paraffin and celloidin. In a few cases the paraffin method was found to be unsuitable on account of the hardness or brittleness of the material. Tbe method of staining that was principally employed was the haomatein and eosin method, methyl eosin being substituted in many cases for the ordinary solution. Gram's method alone, or associated with picrocarmine, safranin, toluidin, sudan, and orange G, was also used, and about 1500 sections were examihed. In the typical cases details of tbe history, clinical symptoms, and treatment were collected. Special attention was paid to the exact description of tbe histological alterations met with.

By way of introduction a brief description of tbe normal epithelium of the hoof, with special reference to the staining affinities of certain cells, is given, so tbat the pathological alterations may be better appreciated.

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ABSTRACTS AND REPORTS. 155

In sections of the normal frog the germinal epithelium when stained with hrematein and eosin shows moderately large oval nuclei stained intensely blue, and lying in a cytoplasm which is of a bluish-red tint. There is a well-marked layer of prickle cells, the cytoplasm of which takes a somewhat more intense red colour, and the nuclei are smaller and shrivelled. External to this there is a layer of granular cells. In this zone the cytoplasm of the cells stains of a brighter red colour, and around the nucleus there are granules of gradually increasing size which possess a strong affinity for hrematoxylin. This substance, which is called keratohyalin, contains small pigment granules. External to this cell differentiation disappears. The first visible nuclei are elongated flattened structures, with rounded pigment granules. They lie in a homogeneous material staining intensely with eosin, and gradually disappear completely, or are recognisable as very small, pale, blue-stained points in the midst of pigment granules. The horn itself is a pale reddish-yellow material without any differentiation.

Horn columns are absent in the frog. Only here and there the horny epithelium is traversed by layers of cells which stain deeply with eosin and are gradually becoming horny.

The germinal layer of the sole stains in exactly the same way as that of the frog. On the other hand, the nuclei of the cells above the basal layer show evidence of more rapid disappearance, as they are hemispherical in shape and their chromatin appears a bright reddish-bllle. This is also seen in the prickle-cell layer, on the intel'- and suprapapillary surfaces, and also on the sides of the papillre. There is no true granular layer.

The interpapillary cells rapidly become elongated flattened structures towards the surface, and they stain, particularly the cytoplasm, an intense red colour. The nuclei become flattened, but still retain their blue colour to begin with. The young interpapillary epithelium which is completely changed into horn stains of a pale reddish-yellow colour. Only traces of red· stained nuclei can be made out here and there, all other structure being lost. The cells covering the papillre undergo a much slower horny transformation.

In the wall the bluish-red germinative layer forms the so-called secondary' horny laminre. The cells are elongated, and are set at an acute angle to the secondary layers of the corium. Their nuclei are large and oval and stain an intense blue. Above the stratified germinative layer there is the red-stained prickle-cell layer. Horny transformation, as evidenced by intense red colouration and the disappearance of the nuclei, is seen in the superficial layers only, and consequently there are no secondary laminre.

Canker of tlte Frog and Soie.-The author describes four cases in which the clinical alild histological examinations gave practically identical results. Clinically the cases presented the usual characters. Microscopic examina­tions of vertical sections through the proliferations showed in the vascular layer a somewhat large number of blood-vessels with rather thickened walls, the majority being seen in cross section. In the tissues surrounding the vessels there were numerous leucocytes and extravasated red blood corpuscles. The papillary layer was well marked. The majority of the papillre were thick and branched at their summits. The blood-vessels of the villi were dilated and congested. The villi were also infiltrated to a moderate extent, the infiltrating cells comprising polynuclear leucocytes, a few acidophile leucocytes, and lymphocytes. Young connective-tissue cells were present in large numbers. There were few extravascular red cells. The epithelial layer was thick and showed no indications of horny transformation. Here and there on the sides of the villi, and to a less extent in a suprapapillary position, there were layers in which the cells

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ABSTRACTS AND REPORTS.

were not differentiated, except that the nuclei were smaller and stained of a deep blue colour. The basal membrane was remarkable for its richness in nuclei, and for the number of nuclei undergoing division. The epithelium in this position was of a reddish-blue colour, and sharply distinguished from the layers external to it on account of the pale blue colour of the latter. In the outward direction the cells were large and well defined. The originally round nuclei changed to an oval shape, were pale blue in colour, and showed a clear margin.

Spaces were present at places in the swollen epithelium. Some of the larger appeared pale red with small oval clear portions, which gave a honeycombed appearance t.o the whole. In the swollen epithelium where degeneration was in progress both healthy and degenerated leucocytes could be seen.

Canker of the Wall.-Microscopic examination of the lesion was made in three cases, and the following is an account of a typical one.

A four-vears-old mare that had had canker of the off hind foot for five weeks. Treatment with silver nitrate had not effected a cure, and the animal had been lame for three weeks. On examination it was found that both frog and sole were affected. Percussion of the wall at the toe gave a hollow sound, and when the case was operated upon it was found that not only the sole but the whole of the anterior part of the wall was undermined. The sensitive lamin<e were much enlarged, and covered with a greasy material. The whole of the diseased tissue was extirpated.

Microscopic Examination.-Three stages of the diseased process could be observed in transverse sections from different parts ofthe affected corium :-

1. Commencing prolifelation of the layers of the corium and ep:thelium, with persisting formation of horny layers.

2. Moderate proliferation and swelling of the epithelium without any horn formation.

3. Excessive proliferation, infiltration, swelling, and destruction of the epithelium.

In the first stage the proliferation principally affects the secondary lamin<e. These lamin<e are often so small that they can only be recognised by the fact that the cells of the germinal layer are arranged in rows. The secondary lamin<e gradually thicken and become club-like at their ends. Each altered primary lamina is surrounded by a broad zone of epithelial cells, to the outer side of which is a narrow layer of cells which stains red. The surface layers of the corium contain a moderate number of blood-vessels, the majority of which are divided longitudinally. The papil\<e at the apices of the lamin<e are particularly vascular. The infiltration principally affects the secondary lamin<e and the papill<e. In the connective tissue there are extravascular blood corpuscles, both red and white. Very few leucocytes are found in the swollen epithelium, and those present are in the form of nuclear fragments.

In the outer layers of the epithelium the nuclei are oval but small, and the cytoplasm appears granular and has a strong affinity for h<ematoxylin. In the layers that stain with eosin all trace of cellular structure is lost. The epithelium gradually passes into the stratum corneum, which is structureless and contains only fragments of nuclei and pigment granules. In many places the transformation into horn is abrupt. Here and there strands of horny tissue penetrate obliquely into the epithelium.

In the second stage of the disease the primary lamin<e are greatly thickened and in cross section show expanded ends. The connective tissue contains large blood-vessels with thickened walls. Infiltration is slight at the bases of the primary lamin<e, but moderately pronounced at their apices. There is no trace of horny transformation anywhere.

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,\USTKACTS AND REPORTS. 157

In the third stage the laminre are very prominent and may measure 900

microns in thickness, the secondary laminre measuring 300 microns. The papilllP may be as long as 2 mm. The smaller lamin re and the papillre are pnncipally affected by the infiltration. In the swollen epithelium there are large collections of rounded cells.

Clinically the cases examined presented the usual symptoms: destruction of the horny wall, more or less proliferation of the corium and epithelium, incomplete horn formation, and exudation. From his clinical and histological observations the author concludes that canker is a chronic proliferative disease of the · corium, in which all strata are involved but principally the papillary layer.

Exposure of the corium to irritation may start the process. As a predis­posihg cause there must be some defect in the horn. Moisture and fermenta­tive changes cause destruction of the horn. The solar surface is principally affected because the horn there is loose in texture and capable of offering very little resistance. Once started, the process leads to the cessation of horn-formation. The undermined horn breaks away as a result of this, and finally the entire solar surface and frog may be left bare as a result of shed­ding of the horn. The proliferation of the papillre and epithelium produces a feathery or villus-like growth. The appearance of the proliferated papillre varies with the original form of the structures. If the papill re are short the resulting growth resembles a cauliflower. The papillre may be as much as 6 cm. long. In very chronic cases the longest are found on the sole. Here the growths are o ften collected together into tufts or clumps which are· yellowish-white at the base and brown or black at the apex. Between the growths there is a greyish-yellow greasy discharge, which has an offensive odour.

In sections examined under the microscope the corium appears loose in texture and hypertrophied. It is composed of swollen connective-tissue bundles and large cells with prominent vacuolated nuclei. Evidence of active tissue production is seen chiefly in the papillre. The primary and secondary papillre are much enlarged, and the formation of tertiary papillre can sometimes be observed.

In those parts of the corium where the papillre are leaf-like the proliferation starts as a rule in the secondary papill re. These may be 850 microns in length but are quite thin. Following this, hyperplasia of the primary papillre· occurs, and they may measure I mm. in thickness.

The connective tissue is very rich in blood-vessels which have thickened walls. The papillre are very vascular, but the vessels have thin walls and are frequently tortuous. There is also a round-celled infiltration. This begins in the perivascular layer of the stratum vasculosum, but is most marked in the papiIJre and lamina!. The infiltration is principally compo!:ed of lympho­cytes, but polynuclear and acidophile leucocytes are also seen. Finally, the latter become so numerous that they quite outnumber the other cells present. E xtravascular red corpuscles are numerously present in the connective tissue, and particularly in that of the tufts. The epithelium of the proliferated lJapillre is multi-layered and no normal horn is produced . The basement . layer is richly nucleated, the nuclei staining intensely with hrematoxylin . . External to this the cells are very swollen. The surface epithelium is. destroyed and desquamated, or, if still present, stains with eosin. Excessive hyperremia may lead to such swelling that the epithelial cells break down,. thus producing gaps in the epithelium.

Observations on Lesir}1ts Caused by Nail Pricks.-It is well known that injuries caused by nails, which lead to inflammation or necrosis of the corium, pedal bone, or fatty frog, produce more or less luxuriant proliferation of the corium and epithelium layers. This is especially so in the case of

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ABST RACTS A:>I n REPORTS.

necrosis associated with perforation of the flexor pedis tendon. These pro­.liferations, which for the most part are found in the lateral lacun~, may be as large as nuts,or are soft flat excrescences which bleed easily if handled and in the middle of which there is generally a fistula. The surface is usually covered with a small quantity of greasy material.

The lesions resemble canker clinically, and this led the author to make microscopic examinations of material derived from four such cases.

The pieces of fresh granulation tissue from the corium and epithelium, removed by operation, were fixed in 4 per cent. formalin-alcohol solution a.nd embedded in paraffin. The sections were stained with hre matoxylin and methyl eosin.

The principal alterations found were as follows ;-In 10ngitudinal sections there was found marked proliferation of the con­

'nective tissue. This principally involved the papill~ of the corium. The 'villi measured up to 4 mm. in length. Some were 400 microns in breadth with branched summits, and others were smaller with club-like ends. There was marked hyper~mia and cellular infiltration of the papillary layer, and the 'villi were especially vascular. The majority of the cells were neutrophile Jeucocytes and lymphocytes, eosinophiles being quite in the minority. Extra­vascular erythrocytes and leucocytes occurred in the epithelial layers and especially between the cells of the germinal layer. The latter was destroyed .at places. Large collections o f red corpuscles were present in the epithelium .covering the hyper~mic papillre. The basement membrane consisted of large cylindrical cells. The cells to the outer side were swollen and con­tained eosin-staining oroplets. Their definite position, varying size (I to 5 ;microns), and lack of structure indIcated their specific nature as cell in­clLlsions. To the outer side there were numerous elongated cells with lirregular outlines, and between these isolated red and white corpuscles were found. At the surface the cells increased in size. Their cytoplasm stained ;faintly and their nuclei were shrunken. Gradually all evidence of cell structure was lost. At places intensely red-stained inclusions were found in the swollen cells.

The Etiology of Canker.-After reviewing the literature on the etiology of ·the disease the author de,cribes some experiments which he made with a view to determining the cause and infectiousness of the condition.

Transplantation experiments were without result, nor could the disease be transmitted by inoculation of the so-called canker pulp into either 'recent or old-standing wounds of the hoof. Attempts to infect a horse already suffering from canker fail ed. Intra-jugular injection of an emulsion ·of canker proliferations produced only a local suppurative lesion. No ·case of spontaneous transmission was observed. No cases of infection occurred when stalls that had been used for horses suffering from canker 'were used without any disinfection for other animals. Bacteria, principally cocci and short bacilli, could be found in sections III the destroyed epithelial masses only. The spirillum described by Jowett as occurring in the dis­

.charge could not be detected. In spite of the negative results of the experiments and the failure to

. detect any bacteria, the author thinks there is much evidence supporting the view that the disease is caused by a specific irritant.

GREASE.

By the term grease is understood a chronic inflammation of the skin of the leg, leading to proliferation and enlargement of the papillre. The epidermis is also involved in the proliferative process. As a rule -.there is no horny transformation, but a greyish-yellow, greasy, offensive

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ABSTRACTS AND REPORTS. 159

layer forms on the surface of the diseased skin. Sometimes this layer is dry and floury. The deeper portion of the cutis and the subcutaneous tissue are involved in the proliferation, producing elephantiasis of the limb affected. As a result of the inflammation the hair is shed to some extent.

After reviewing the literature on the subject, the author gives his own observations and experiments in detail.

The resemblance between grease and canker cannot be denied, and it was this fact that prompted the author to carry out his investigations, especially from the point of view of the histology of the lesion.

The material submitted to examination was obtained from five cases of grease, and the sections examined were treated in the same way as those from the cases of canker. C'inically the cases under observation presented all the usual symptoms.

Microscopic Examination.-In vertical section the warty outgrowths are found to be very large and separated from each other by deep clefts. The basis of the outgrowths is formed of connective- issue cores, the larger of which divide into a number of branches. The blood-vessels appear dilated. The number of hair follicles is small, and those that are present are shrunken and contain no hairs. There is an extensive round­celled infiltration in the connective tissue, and especially in the apices of the outgrowths. In some of the connective-tissue cores acidophile leucocytes are in such large numbers as to give the section a bright eosin tint when examined under a low power. The most superficial layers of the epith~lium are swollen in the process of destruction and desquamation. There is frequently also a marked round-celled infiltration. The inner epithelial zone is penetrated at places with streaks of horny material derived from the degenerating layer. The epithelium in the deepest portions of the clefts is also infiltrated. The nuclei in the germinal layer are large, oval, and vacuolated. Red-stained streaks, which show a tendency to horn-formation and containing long narrow nuclei which stain an intense blue, are to be seen in the outer layers of the epithelium. There is no difterentiation mto cells in the degenerated epithelial layer. The basal layer is invaded by leucocytes, and here and there an intact eosinophile leucocyte is noticeable.

The question as to whether there is any connection between canker and grease, and whether the lesions of the two diseases are identical, has often been raised in literature, and answered in different ways.

The author made observations in this connection in three cases, in two of which microscopic examinations were undertaken.

In the first case of grease examined the lesions involved not only the skin but also the bulbs of the heels and the median lacuna of the frog.

In the second case there was canker of the frog, sole, and wall, and the papillary proliferations extended on to the skin of the bulbs of the heels.

In the third case the lesions were similar, but the skin alterations were more extensive, excrescences being present on he skin as far up the leg as the fetlock.

The alterations seen in grease consist of wart-like proliferations of the skin. The enlarged papillce may measure as mllch as 4 cm. in length. There is either a greasy or floury secretion on the surface.

In the proliferative processes involving the connective tissue, and especially in chronic cases, there is thickening of the subcorial and subcutaneous tissues. The subcutaneous layer may be 3 cm. in thickness. The greater part of the hair falls out. In vertical sections thepapillce show a much branched structure. There is a large amount of newly formed connective tissue, especially in the ends of the papillce. This tissue is well supplied

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160 ABSTRACTS AND REPORTS.

with blood-vessels, and in some places there are extravasations of blood Most of the hair follicles are empty and shrunken. The epithelium is very thic;k and swollen. The surface epithelium, both on the summits of the papill::e and in the depressions between them, is degenerated. There is no normal horny transformation. Here and there streaks of flattened epithelium with a strong affinity for eosin are seen, but the cells are still nucleI' ted.

The connective tissue of the papill::e is always infiltrated with leucocytes, and lymphocytes and neutrophile leucocytes also invade the epithelium. Cocci and short bacilli are demonstrable in the degenerated epithelium, but no bacteria can be found in the connective tissue. The inflammation and proliferation of the deep corial layers and the subcutaneous tissue in chronic cases produces elephantiasis. The proliferation of the connective tissue is accompanied by an abnormal epithelial formation, which does not become horny but degenerates.

The disease is best described by the name suggested by Moller-chronic verrucose dermatitis. Grease and canker of the foot and frog must be considered as identical conditions, because of the absolute similarity of the pathological alterations in the two diseases. The best proof of their identity is the fact that by the extension of the one the other is produced: thus, primary canker may be followed by grease. The lesions of secondary grease exactly resemble those of the primary condition. The coexistence of the two conditions is of not very frequent occurrence, the author having observed it in only four cases out of forty-five.

The Treatment of Canker and Grease.-References to the treatment of canker in literature are numerous. The author has been able to collect more than a hundred. In text-books the treatments given may be divided into three groups: The application of medicaments, the mixed methods, and the purely operative treatments.

He has collected details of twenty·one serious cases of canker, including the type of the disease, the treatment adopted, the results, and the duration of the treatment. From a practical point of view the outstanding fact is that the treatment must be a long one. In the author's cases the average period of treatment was 76 days; shortest 40, longest 136. It will there­fore be seen that treatment should only be resorted to in the case of valuable or young animals. The disease must not be too advanced. When the frog and sole only are affected the disease is generally curable. The same may be said of cases in which only one side of the wall or the toe is affected. When larger portions of the wall are affected, and sequel::e are present in the form of rotation of the pedal bone about its horizontal axis or sinking of the pedal bone, results are doubtful.

When treatment is undertaken it must be very thoroughly carried out,­upon that point all authors are agreed.

If the proliferations are not too extensive treatment by medicaments may be successful. . The author has had the best results by the repeated application of 5 to 10 per cent. formalin, lead nitrate, or sublimate, after removal of all the undermined horn. The sublimate may be applied either as a powder or in the form of moistened tablets smeared carefully over the affected parts. The hoof should always be bandaged. It is important to protect the diseased part from moisture, and particularly from the effects of ammonia from the f::eces or urine.

The hoof must be carefully watched so that all destroyed proliferations and excretion may be removed, and the bandages renewed. Any fresh pro­liferations must be treated with a repetition of the dressing.

Where the disease is wide-spread surgical interference is indispensable. The diseased hoof must be cut away and the wound cleansed under a general or local an::esthetic. After the removal of the horn every trace of diseased

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ABSTRACTS AND REPORTS.

corium may be completely removed if an Esmarch elastic bandage be applied. In his earlier cases the author used the knife to remove the bulk of the pro­liferations, completing the process with an autocautery, or, in cases that were not so advanced, using the cautery only. In his later cases, however, he used the hot iron only for the total removal of the diseased corium. By so doing the healing process is cut short, and there is the great advantage that there is little or no bleeding.

Subsequent treatment consists in the apnlication of iodine iodoform gauze or other wound dressings. Cleanliness and dryness of the surface of the wound are the principal considerations, medicaments playing a quite secondary part in the process of healing.

Relapses must be carefully watched for. They occurred in sixteen out of twenty-one of the author's cases. A relapse is recognised by a rapid elevation and by the soft consistence of the whitish-yellow epithelium. Such areas, if smail, may be treated with medicaments only. If more extensive operation is necessary,-in his earlier cases the author resorted to the use of the hot iron, but later he used the knife in such cases.

Bandages should be changed every three or four days. Relapses some­times occur when healing has been apparently complete. The author had two such cases. The utmost care and cleanliness are essential, and the diseased foot should be smeared with tar from time to time. Grease is a very obstinate condition to treat, and if the disease be extensive treatment is hardly warranted.

In cases where the disease is limited in extent the best results have been obtained by removing the lesions with the knife and the subsequent applica­tion of caustics and bandages. Long-continued treatment is necessary, and relapses may render a repetition of the surgical interference or cauterisation imperative. c (Burgi, Schwet'zer Archiv fur. Tierheilk., Vol. LII., Nos. 3, 4, and 5. 1910, pp., 137-161, 207-228, 293-336.)

THE ARTIFICIAL TRANSMISSION OF EAST COAST FEVER.

THE primary object of the following experiments was to find out whether the transplantation of entire organs from sick animals into susceptible ones would convey the disease. A positive result attending the first attempt, further experiments followed as a matter of course. An additional impetus was given to the experiments, and a definite line of working indicated, by the demon­stration of the possibility of puncturing the spleen of an animal during life.

In all, seven series of experiments were devised, involving the use of various materials for inoculation and a variety of methods of administration.

The following is a skeleton of the plan adopted :­Experiment 1. Intraperitoneal insertions and injections­Group A. Insertion of the whole spleen. Group B. Insertion of pieces of spleen. Group C. Injection of spleen pulp. Group D. Insertion of lymphatic glands. Group E. Injection of the juice of lymphatic glands. Group F. Injection of blood. Experiment II. Intrasplenic injections-Group A. Injections of spleen pulp. Group B. Injections of lymphatic gland juice. Group C. Injections of blood. Experiment III. Intralymphal injections­Group A. InjectIons of spleen pulp. Group B. Injections of lymphatic gland juice. Group C. Engrafting lymphatic gland. Group D. Injections of blood.

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