Sometimes the physician finds that he must be satisfied for the present with but a partial view of the case before him. He sees that there are some agencies at work, which are hidden from his view. Under such circumstances, while the careless and adventurous practitioner makes up his theory of the case confidently, and acts upon it, supplying what is not known from his own imagination, and mingling all together in one confused mass; the judicious physician, on the other hand, cautiously distinguishes between what he actually knows and what may be supposed, acts upon this knowledge, and watches for farther developments to clear up what is doubtful. He treats the case according to the indications of the presenting symptoms, carefully scrutinizing the effects of his remedies. Perhaps he succeeds in cutting off at first some of the tributaries of the disease; and, by so doing, patiently and perseveringly, he at length comes at the main disease—the starting point of the whole case. In pointing out the characteristics of medical skill, allusion was made to the quantities and forms in which remedies are administered. These must, of course, be varied to suit each individual case. Sometimes a very nice adaptation is necessary, especially in regard to quantity. A remedy, which is appropriate to a case, may be given in such a quantity as to be injurious. The use of a medicine may be continued too long. It may have accomplished all the good that it can; and the continuance of it will do harm, perhaps even beyond the undoing of all the good which it has effected. Sometimes a change occurs in the condition of the patient of such a character, that a remedy, which has been up to that time beneficial in its influence, will now produce bad results. Medicine is often continued under such circumstances. Such are some of the errors to which the physician is liable in regard to the quantity of medicine to be given, if he be at all loose in his habits of observation.