ceases and the entire range of chemical and physical activities with which we are acquainted either cease, or, it may be, assume an entirely new role. This temperature again is far below that at which any chemical reaction is known to take place. The fact, then, that life can continue to exist under such conditions affords new ground for reflection as to whether after all life is dependent for its continuance on chemical reactions. We, as biologists, therefore follow with the keenest interest Professor Dewar's heroic attempts to reach the absolute zero of temperature; meanwhile, his success has already led us to reconsider many of the main issues of the problem. And by having afforded us a new realm in which to experiment, Professor Dewar has placed in our hands an agent of investigation from the effective use of which we who are working at the subject at least hope to gain a little further insight into the great mystery of life itself.