The external causes are known by the patients own indications. If cardiaca come from the defect268 of another member, it is recognised by that sickness and its signs. If it come from the blood,269 it will be recognised by those things, that are natural, unnatural or contrary to nature. If the urine be red and thick, the pulse undulating, the face red, and there be heat round the neck,270 and the patient suffer extreme thirst, and he be young, liberal,271 and jolly, and favour foods that increase sanguine humour, then it is right to say the cardiaca comes from sanguine humour. If the urine be thin and yellow, the pulse rapid, accompanied by great heat, and the patient be used to hard work and running, and foods that engender