THE first Greek poet of whose personality we are certain, Arctinus of Lesbos (BC 770), sharply differentiated medicine and surgery, and held medicine responsible for the advancement of medical science. He relates how Esculapius" endowed one of his sons with nobler gifts than the other; for while to the one, Machaon, he gave skilled hands to draw out darts,-make incisions and heal sores and wounds, he placed in the heart of the other, Podilarius, all cunning to find out things invisible and cure that which healed not." How can we, disciples of Podilarius, best proceed in this day and generation to" find out things invisible and cure that which heals not"? The problem is as old as medicine itself The story of medical investigation unfolds itself in the history of medicine. Progress comes through ideas. Great investigators have appeared from timeto time in medicine. They have contributed new ideas, in the elaboration of which they recordednew observations, recognized new facts, established laws, advanced the art of practise, and thus developed the science of medicine. As time passed the so-called underlying or fundamental sciences evolved, and inturn made fresh opportunities for the medical investigator, but they have taken a large proportion of medical investigators from the field of active practise. Some are still left who are attempting to" find out things invisible" and to solve the ever-present'problems of treatment of the sick. Recently, to further such ends, a national Society for Clinical Investigation was cre-ated (1909). According to the constitution the objects ofthis society are" the cultivation