THE RESEARCHES OF DRIESCH.--Just as modern physics is concerned with the infinitely small--the ultra-microscopic, in fact--so modern biologists are concentrating attention upon microscopic organisms, where life is seen at its lowest terms, and where (if anywhere) they may expect to discover what are the _differentia_ of life, i.e. what are the qualities that distinguish living organic from inorganic matter. Perhaps the most notable of the researches conducted in this sphere, of recent years, have been those of Professor Driesch, who expounded his results in the _Gifford Lectures_ for 1907-1908 (_The Science and Philosophy of the Organism_). The phenomena upon which Driesch lays considerable stress are those which occur upon a division of certain living embryos. An embryo, when cut in half, displays remarkable powers of self-adjustment and continued development. Each half can, as it were, regulate itself, and make a fresh start; a process which results in two self-contained organisms, though of smaller size than would have resulted from a single undivided organism. The cells which compose the organism seem able to adapt themselves to whatever demands are made upon them. Like workmen building a bridge, all of them _can_ do every single act--if need arise--and the result of their labours is a perfect bridge, even if some of the workmen fall sick or are killed or injured in an accident. Driesch sums up the results of his researches by saying: "There is something in the organism's behaviour--in the widest sense of the word--which is opposed to an inorganic resolution of the same (i.e. to its complete expression in terms of chemistry and physics), and which shows that the living organism is more than a sum or aggregate of its parts; that it is insufficient to call the organism 'a typically combined body' (i.e., a machine), without further explanation."[73]