When we take into consideration that faeces contain a highly poisonous substance, which may be separated from them by dialysis, their retention by constipation, must more or less induce stercoraemia. a causing ill health, and in disease becoming a serious complication.

There is a fever of non-elimination with a feeling of languor, headache, the tongue is coated, the breath offensive, and the bowels constipated. The physician fears typhoid fever, but finds that a good brisk cathartic dissipates all the unpleasant symptoms, and the temperature falls to the normal. This fever is also liable to appear among those who are confined to bed from other causes. b No one who has watched cases of acute diseases, such as pneumonia, can have failed to see how a rise of temperature sometimes coincides with the occurrence of constipation, and is removed by opening the bowels. c The surgeon and obstetrician have cause often to rejoice when they have found a fever which they feared indicated septicaemia disappearing after free purgation. d

As a curative agent, the saline cathartics stand at the head of all others in the treatment of general dropsy, ascites, mania, rheumatic and gouty irritation of the cerebrum, hyperaemia of the brain, congestion of the portal circulation, and in cases of retained renal secretion, to aid in separating the products of retrograde metamorphosis from the blood, etc. Many valuable hints can be gleaned from the exhaustive investigation of the action of saline cathartics by Dr. Matthew Hay. The following are the results as formulated by himself:

1. A saline purgative always excites more or less secretion from the alimentary canal. depending on the amount of the salt and the strength of its solution, and varying with the nature of the salt.

2. The excito-secretory action of the salt is probably due to the bitterness as well as to the irritant and specific properties of the salt, and not to osmosis

3. The low diffusibility of the salt impedes the absorption of the secreted fluid.

4. Between the stimulated secretion on the one hand, and impeded absorption on the other, there is an accumulation of fluid in the canal.

5. The accumulated fluid, partly from ordinary dynamical laws, partly from a gentle stimulation of the peristaltic movements excited by distention, reaches the rectum and produces purgation.

6. Purgation will not ensue if water be withheld from the diet for one or two days previous to the administration of the salt in a concentrated form.

7. The want of purgation is not due to the want of water in the alimentary canal, but to its deficiency in the blood.

8. Under ordinary conditions, with an unrestricted supply of water, the maximal amount of fluid accumulated within the canal corresponds very nearly to the quantity of water required to form a five or six per cent. solution of the amount of salt administered.

9. If, therefore, a solution of this strength be given, it does not increase in bulk.

10. If a solution of greater strength be administered it rapidly increases in volume until the maximum is attained. This it accomplishes in a case of a twenty per cent. solution in from one to one and a half hours.

11. After the maximum has been reached, the fluid begins gradually and slowly to diminish in quantity.

12. Caeteris paribus, the weaker, or in other words the more voluminous the solution of the salt administered is, the more quickly is the maximum within the canal reached, and accordingly purgation follows with greater rapidity.

13. Unless the solution of the salt is more concentrated than ten per cent., it excites little or no action in the stomach.

aBouchard. cbrunton.

b Dr. Victor C. Vaughan. df. G. Novy.

14. The salt is absorbed with extreme slowness by the stomach of the cat.

15. The salt excites an active secretion in the intestines, and probably for the most part in the small intestine, all portions of this viscus being capable of yielding the secretion in almost equal quantities.

16. The bile and pancreatic juice participate very little in the secretion.

17. The secretion is probably a true succus entericus, resembling the secretion obtained by Moreau after the division of the mesenteric nerves.

18. The secretion is promoted by local irritation of the intestines, as by ligatures, but only in the immediate locality or site of the irritation.

19. Absorption by the intestines generally is reflexly stimulated by such irritation, (the effect of numerous ligatures applied at points remote from the seat of the injected salt being to diminish the amount of purgative fluid by accelerated absorption).

20. If the salt solution be injected directly into the small intestine, the stronger within certain limits the solution is, the greater will be the accumulation of fluid within the intestine.

21. This difference is not observed when the salt is administered per os, as the strong solution becomes diluted in the stomach and duodenum before passing into the intestine generally.

22. The difference is due to the local action of the salt on the mucous membrane, and probably more to an impeded absorption than a stimulated secretion.

23. When the salt is administered in the usual manner, it appears in the case of sulphate of magnesium and of sulphate of sodium, to become split up in the small intestine, the acid being more rapidly absorbed than the base.

24. A portion of the absorbed acid shortly afterwards returns to the intestines.

25. After the maximum of excretion of the acid has been reached, the salt begins very slowly and gradually to disappear by absorption, which is checked only by the occurrence of purgation.

26. During the alternations of absorption and secretion of the acid, it is the salt left within the intestines which excites secretion, the absorbed and excreted acid exerting no such action while in the blood, or during the process of its excretion, as Headland believed.

27. The salt does not purge when injected into the blood, and excites no intestinal secretion.

28. Nor does it purge when injected subcutaneously, unless in virtue of its causing local irritation of the abdominal subcutaneous tissue, which acts reflexly on the intestines, dilating their blood vessels, and perhaps stimulating their muscular movements.

29. The sulphate of sodium exhibits no poisonous action when injected in the circulation.

30. The sulphate of magnesium is, on the other hand, powerfully toxic when so injected, paralyzing first the respiration and afterwards the heart, and abolishing sensation or paralyzing the sensory motar reflex centres.

31. Both salts, when administered in the usual manner produce a gradual but well marked increase in the tension of the pulse.

32. According as the salt solution within the intestine increases in amount, there occurs a corresponding diminution of the fluids of the blood.

33. The blood recoups itself in a short time by absorbing from the tissues a nearly equal quantity of their fluids.

34. The salt after some hours causes diuresis, and with it a second concentration of the blood, which continues so long as the diuresis is active.

35. As the intestinal secretion excited by the contents is a very small proportion of organic matter as compared with the inorganic matter, the purgative removes more of the latter than of the former from the blood. In certain cases a large quantity of the salts of the blood is thus evacuated.

36. The amount of the normal constituents of the urine is not affected by the salt.

37. After the administration of sulphate of magnesium, much more of the acid than of the base is excreted in the urine.

38. The salt has no specific action in lowering the internal temperature of the body, or if it possesses any influence that way it is to a very small extent.

39. It reduces, however, the absolute amount of heat in the body.

V