By diarrhoea is meant frequent discharges of loose or fluid evacuations, depending on derangeinent of the intestinal mucous membrane, including the secretory glands connected therewith.

* For the dose, refer to the " Introductory Remarks." † See "Glystering," in the Appendix.

Diarrhoea may attack dogs at any age, as dogs of all ages are alike exposed to the operation of the various causes which excite the disorder; but, everything being equal, it is most frequent in pups, and in old, fat, and idle dogs. It sometimes prevails as an epidemic, begotten of obscure and unknown causes.

Diarrhoea may occur as a specific independent morbid state, or as an occasional or constant symptom of several different disorders.

Diarrhoea presents two typical states - the acute and the chronic; and the general symptoms vary accordingly.

The acute state may be preceded or accompanied by colicky sufferings; acrid, offensive matter is thrown up from the stomach; the vomiting, which is an early symptom, is often persistent and difficult to subdue; the vomit is not relished as a meal, as is the dog's custom; the pulse is somewhat accelerated; the thirst constant and urgent; and the belly slightly tender to the touch. The discharges are voided without much or any effort, and for a brief time relieve the dog's uneasiness. The evacuations are at first feculent, but soon become looser, more watery, more scanty, and more mucous, - the strength decreasing in proportion as the discharges are more frequent and more profuse. Their frequency varies according to various circumstances, which need not be dwelt upon. Their character, as regards colour, consistence, smell, etc., vary according to the primary cause, the duration of the disorder, etc.; and it is not unusual to observe bile, mucus, and faeces in the same evacuation. When the disease is about to terminate in death, blood in some cases issues from one end, or from both ends of the intestinal canal; but in the majority of cases exhaustion, preceded by cold mouth and unconsciousness, terminates life.

The chronic state differs from the acute rather in its march than in its symptoms. The disease makes slower progress, and its duration is longer. Weakness from the excessive and long-continued discharge is a prominent feature. The anus is protruded and red, and shows haemorrhoidal distention. Death is ushered in by utter prostration of the system, and by paralysis of the hind legs.

The foregoing general characters of diarrhoea are variously modified, according to particular causes. Diarrhoea may be set up by eating too much food - in which case the stomach is unable to digest the excess and the crude matter passes into and irritates the bowels; by eating food of an improper or indigestible nature; by the presence in the bowels of worms, or of any foreign body, such as a ball of hair, or any other substance that resists digestive action. By these different agents, irritation is set up in the mucous membrane, and mucus, in quantities more or less considerable, is poured forth. This process may be regarded as a natural effort to expel the offending material, whatever that may be, and so to prevent the serious consequences that would otherwise ensue. The quantity and frequency of the discharge depend on the intensity of the irritation. There are sickness, foul breath, and liquid, frothy or watery evacuations; but little or no feverishness. The diarrhoea ceases spontaneously on the removal of its cause; although some looseness will probably continue for a short time afterwards.

Diarrhoea may also be caused by accumulations of hardened faeces, setting up irritation and excessive mucous secretion. Small quantities of mucus, either pure or intermixed with feculent matter, are discharged frequently and with some straining. If, as is not unfrequent, astringents be given for such a case as this, in ignorance of the true cause of the purging, the result is that the constipation is increased, and intestinal obstruction rendered imminent.

Acrid bile, or even an unusual quantity of healthy bile, often excites diarrhoea in dogs, by increasing both the secretory and contractile functions of the intestinal canal. There is co-etaneous disorder of the liver giving rise to unhealthy or excessive secretion of bile, which, when in the bowels, causes irritation, and even inflammation of the mucous surface. Sudden vomiting comes on, followed by purging. The sickness is generally of a severe and obstinate character; the evacuations are voided with pain, and, like the vomit, are black or yellow, and very offensive. The stools, which are at first feculent, subsequently consist of glairy mucus, either alone or mixed with bile. Unless relief be given, great exhaustion and prostration of strength ensue, under which the dog sinks.

Diarrhoea may exist as a symptom of inflamma-tion of the mucous membrane of the bowel caused by irritant poisons, which have not been vomited back. The dejections are frequent and bloody, and the thirst extreme. The abuse of calomel or some other mercurial preparation - that is, giving mercury in wrong cases, or in wrong doses - is a very frequent cause of excessive purging. Large doses are almost always vomited - thanks to the irritability of the dog's stomach - but a smaller quantity will pass into the bowels and act as a powerful drastic purge. Meyrick states that the congestion of the mucous membrane, which is the cause of his "chronic diarrhoea," can best be removed "by giving very small doses of mercurial preparation," viz., two grains of grey powder, every two hours for two days - twenty-four grains in all. Surely these are not "very small doses!". He very properly, and of necessity, goes on to remark - "Great caution must be used in giving the grey powder; if it is observed to irritate the bowels, as evidenced by an aggravation of the diarrhoea, it should be immediately stopped for a time" Mercury produces diarrhoea and cures diarrhoea, which is equal to saying, similia similibus curantur; but mercury will not cure diarrhoea unless it be given in doses too small to set up a diarrhoea of its own. Mercury is an invaluable remedy in proper doses for certain diseases with diarrhoeaic symptoms; but it is a rank poison in improper doses, and in improper cases. More dogs die of mercury, than of the diseases against which it is administered.

Diarrhoea is a frequent and unfavourable complication of distemper. Further remarks on this point will be found when referring to the major disease.

Treatment

Some cases of diarrhoea are best left alone; they cure themselves, especially when they depend on the presence of irritants, upon the natural expulsion of which the purging ceases. This rule should be observed more particularly when the evacuations deviate from the natural character only in being unusually loose, and when the disorder can be traced to improper food in quantity or quality.

Demulcents and diluents - suet boiled in milk, barley-water, rice-water, arrow-root, etc. - have a good effect in facilitating the discharge of acrid food, foreign bodies, or hardened faeces; they also soothe the irritated mucous membrane, and so far relieve pain.

Injections * of warm water alone or mixed with starch, act as in internal fomentation and assuage pain.

* See " Glystering," in the Appendix.

The diet should be strictly regulated from the beginning to the end of the case, and even for some time after recovery. Light bland food, such as arrow-root, Indian-corn flour, rice, thickened with milk or gravy, or beef-tea, should be placed before the animal, or if necessary given to it, frequently and in small quantities.

The following are the most efficacious remedies in this disease: -

Aconilum * when the diarrhoea is symptomatic of congestion of the mucous membrane of the intestines, and caused by exposure to cold and damp; and when there are feverishness, vomiting, watery or slimy discharges, thirst, and pains in the bowels.

Mercurius when the evacuations are slimy or bilious, or bloody; when the anus is red and excoriated; the pains severe and colicky.

Arsenicum is indicated when the motions are watery and frequent, and followed by sunken countenance, cold legs, weak pulse, and exhaustion.

China is suitable for chronic diarrhoea, attended with the passage of undigested food, failure of strength, slimy tongue, and brownish motions.

Chamomilla, Phosphorus, Sulphur, and Nitric Acid are adapted to particular cases, but in the majority of cases the above four remedies will be found of most service.

* For the dose of these medicines, see "Introductory Remarks."

Food, Etc

During the attack, the best diet is beef-tea thickened with ground rice. Solid food must be given with great caution during convalescence. Cold food is better than hot during the diarrhoea. It is important to keep the external parts thoroughly clean by washing with lukewarm water and soap two or three times a-day.