In proof of the sensation of thirst being greatly dependent upon the quantity of fluid circulating in the vessels, Professor Dunglison of Maryland refers to the fact, mentioned by Dupuytren, that he “succeeded in allaying the thirst of animals by injecting milk, whey, water, and other fluids into their veins;” and to Orfila’s statement, “that, in his toxicological experiments, he frequently allayed, in this way, the excessive thirst of animals to which he had administered poison, and which were incapable of drinking, owing to the œsophagus having been tied. He found, also, that the blood of animals was more and more deprived of its watery portions as the abstinence from liquids was more prolonged;”[59] and hence the greater thirst naturally experienced under such circumstances. As a general rule, then, the desire for liquids will in itself be an indication of their propriety; but in gratifying it, we should be careful not to drink so fast as either to distend the stomach beyond proper bounds, or to disturb the progress of digestion by undue dilution too soon after eating. Many persons, from habit rather than thirst, impair the tone of the stomach by drinking largely during or immediately after meals, and thus relaxing the mucous coat, and probably affecting the quality of its secretions. If the gastric juice be greatly diluted by extraneous fluids, it is natural to suppose that its solvent power must be diminished; but whether this explanation be sound or not, the practice of drinking frequently is certainly hurtful, and therefore we ought to avoid it. Experience proves that a moderate quantity of liquid during a meal is beneficial; and if we drink little at a time, the risk of exceeding the proper limit will be very small. Dyspeptics, however, ought to be on their guard against taking too much, as they are apt to be misled by uneasy sensations in the region of the stomach, which are relieved for the moment, but afterwards aggravated, by the free dilution of the food. Those, also, who live well, and are in the habit of taking wine daily whether the system requires it or not, often fall into the error of excessive indulgence in liquids to mitigate the thirst and irritability which the unnecessary use of stimulus never fails to induce, especially at night. The continual dilution, however, adds to the mischief, by increasing the debility of the stomach, and, as pointed out in the chapter on Thirst, the only effectual remedy is to adapt the diet and regimen to the real wants of the constitution. Except in disease, a continually recurring thirst must proceed from mismanagement, and it is to be satisfied by an improved and rational regimen, and not by oceans of fluid, which only weaken the stomach still more, and aggravate the craving they are meant to cure.