Growth Normal and Abnormal

Abstract

Growth as we see it in an animal or a plant, is a smooth continuous process. But the more we delve into it, the more discontinuous we find it to be. Individual cells do not grow indefinitely. When they reach a certain size, they undergo a drastic reorganisation, and divide into two. Even growth between one division and the next is not, as one might have expected, a smooth process of increase by compound interest. Instead, as Dr. J. M. Mitchison of Edinburgh University has recently shown, it is growth by simple interest, until shortly before the cells are due to divide, when they suddenly double their rate of increase, in readiness for the appearance of two daughter cells, each of which will grow at the original rate. The machinery for making new living matter is evidently duplicated quite suddenly.