The Chemical Basis of Growth and Senescence

Abstract

THE physicist who theorises is more fortunate than the biologist. He may elaborate theoretical considerations for the whole of his life and still be talking sense at the end of it. It is hard for the biologist to theorise for five minutes without talking nonsense. Yet biologists., in spite of all the warnings of the past, find the theoretical impulse irresistible, and sometimes it is useful for them to give way to it. Not that their theories are likely to be true, but that they usually raise such acute opposition on the part of other biologists that the others devise experiments to refute them, and much valuable information is obtained. Not all theories have this salutary effect. Some act as intellectual soporifics providing attractive names, the frequent repetition of which hypnotises the hearers and stops all further inquiry. Of all the words that possess this “virtus dormitiva,” there has been none greater than Weismann's “germ plasm.” The “germ plasm,” so far as we understand it, is a hypothetical substance with magical properties, which exists in living cells and enables them to divide. Some of it is infinitely divisible, and the possessors of this sort are germ cells; some of it resembles ordinary matter in being finitely divisible, and cells that possess this sort are somatic cells. Perhaps this statement is erroneous and the theory is not quite so bad really, but if so the difference is too subtle to have been grasped by its adherents or opponents.

The Chemical Basis of Growth and Senescence.

By Prof. T. Brailsford Robertson. (Monographs on Experimental Biology.) Pp. viii + 389. (Philadelphia and London: J. B. Lippincott Co., 1923.) 12s. 6d. net.