M. Dordonville is the most recent author on the Spa waters, as he has resided there for many years, on account of his own health. According to him, the first perceptible effect of drinking the Spa waters, especially if taken on an empty stomach, is a slight affection of the head resembling that which results from taking champaign. Four or five glasses suffice to produce this phenomenon, especially at first. As this arises from the carbonic acid gas, it is very transitory. This abundance of gas renders these waters very pleasant to drink, but they are far from agreeable when the gas has escaped—and they are then less easy of digestion. Hence the bottled waters are far less efficacious than at the sources. Since the mania of Broussais, it has not been uncommon for French visitors to take the waters mixed with gum Arabic, by which precious mess the springs were rendered nauseous and indigestible. We may agree with Dr. Dordonville that the action of Spa waters is not confined to the stomach, but extends to various organs with which the stomach is bound in sympathy. This applies to debility of the digestive organs and its consequences; but we must be cautious how we employ this chalybeate where there are any obstructions or engorgements of other viscera, merely because they are diuretic, and promote absorption. Both De Steers of old, and Monsr. Dordonville, of the present day, assure us that these waters require to be taken in large doses, and for a considerable time, otherwise they will do harm instead of good. “Those who cannot take them in this manner ought to desist from taking them at all.” Mons. D. has seen many people who have taken from 300 to 350 ounces of the waters daily. PETER THE GREAT generally took twenty-one glasses (three ounces each) every morning. Dr. D. however, wisely leaves it to the feelings of the patient, how many goblets he daily takes. These waters have been found very beneficial in chronic diarrhœa, as might indeed be expected; but _large quantities_ of any liquid taken in such cases, are detrimental, especially when conjoined with the pedestrian exercises that are recommended. We can hardly subscribe to the doctrine that these chalybeates are beneficial in obstructions of the liver, and enlargments of the spleen—especially the former, considering that they have no aperient quality. The same observation applies to enlargement of the mesenteric glands. On the kidneys they have an evident action, and DE STEERS, the Sydenham of his day, calls them _vesical_. “The waters of Spa remove heat of the kidneys and bladder, and expel gravel more effectually than any other remedy.” One of the most general effects of these waters is an increase of appetite, and most patients acquire flesh as well as strength under their use.