As a student, I used to enjoy ’Karsten and Schenck’ propped up on the breakfast-table. With equal familiarity I treated ’Kerner’, 'Schimper', and other great picture-books of botany. The time came to translate the dreams of youth into vocation. ”Protista”, said the professor of zoology, ”are the pivot of biology”. I substituted my breakfast-reading with the Archiv für Protistenkunde, and hesitated at the coming call of biophysics. Ever since I have been rent, like the morning toast, by two forces which would make of me a student of the microcosm of protoplasm and a disciple of its greatness. They are the forces splitting biology into macromolecules and macro-organisms, and I do not know how this rift may be spanned. I cannot conceive what energy level, chemical bond, or carbon-grouping can decide whether it is insect-pollination or curiosity that will be inherited. But the pendulum has swung. The young botanist no longer looks at these books? he models molecules and chromosomes, and works very largely in vitro. Nevertheless, if biology is not to stand still, the pendulum will return and its amplitude will be the strength of those who have put their trust in the macrocosm. These were the thoughts which I vaguely entertained, when I found myself in the forests of Malaya and I measured my insignificance against the quiet majesty of the trees. All botanists should be humble. From trampling weeds and cutting lawns they should go where they are lost in the immense structure of the forest. It is built in surpassing beauty without any of the necessities of human endeavour; no muscle or machine, no sense-organ or instrument, no thought or blueprint has hoisted it up. It has grown by plant-nature to a stature and complexity exceeding any presentiment that can be gathered from books, and it is one of the most baffling problems of biology.