We have already seen that the channel through which the poison leaves the body is mainly the fæces. Treatment must therefore be directed, as in the former instance (lead absorption), towards eliminating the poison by this means as much as possible, both by the use of enemata, and later the use of sulphate of magnesia, which may be added to the ordinary fluid enema; and it is far better in obstinate cases of constipation and colic to give enemata than to continue with the huge doses of salines or other aperients, such as croton-oil, elaterinum, or castor-oil. =Colic.=--Lead colic may be simple, acute, recurrent, or chronic and continued. In whatever form colic appears pain is invariably referred to the lower part of the abdomen, frequently into the groins, and occasionally to the umbilicus. The pain has to be distinguished particularly from acute gastritis, and occasionally from appendicitis, and sometimes from that of typhoid fever. Acute colitis--not common in this country--and dysentery, may, to some extent, simulate the pain of lead colic, but John Hunter’s[2] original definition of “dry bellyache” conveys very vividly the type of pain. Occasionally diarrhœa may be met with, but as a rule obstinate constipation is present. In continued colic, or chronic colic, sometimes lasting for several months, obstinate constipation is the rule. In the simple acute colic the pain passes off in the course of five or six days, generally disappearing about four days after the lower intestine has been thoroughly cleared. The pain of lead colic is relieved by pressure upon the abdomen, whereas that of gastritis and most other forms of abdominal pain may be generally elicited along the descending colon and splenic flexure; mucus is commonly found in the stools, especially the first evacuation, after obstinate constipation occasionally of several days’ duration associated with an ordinary attack of lead colic. Blood may be passed, but this symptom is not common. The pain in the acute form is paroxysmal; it is rarely persistent, being typically intermittent. During the paroxysm distinct slowing of the pulse-rate with an increased blood-pressure takes place, and the administration of vaso-dilators--such, for instance, as amyl nitrite--during a paroxysm rapidly relieves the pain and lowers the blood-pressure, and in this way distinguishes acute colic of lead poisoning from, say, subacute appendicitis. Vomiting may or may not be present, though the patient usually complains of feeling sick, but there may be at times vomiting of a frothy mucus. It is unusual for a patient to die from acute colic, but acute paroxysms have been recorded in which yielding of the blood-vessels of the brain has occurred.