The Great Chain of Life

2. Machinery for Evolution

2. Machinery for Evolution ENTER LOVE AND ENTER DEATH ON THE SECOND of January 1700 Anthony van Leeuwenhoek, draper of Delft and self-taught Columbus of the littlest world, was writing to the Royal Society of London one of the many letters in which he described his voyages of discovery within a drop of water. To William Dampier and other such rovers he left the exploration of the terrestrial globe. To another contemporary he left those equally adventurous voyages "through strange seas of thought, alone" which took Newton across abysses of space to spheres much larger but not so little known as those to which Leeuwenhoek devoted his long life. These worlds of his were not lifeless but teaming with life; and his discoveries, unlike those of Columbus, were discoveries in an absolute sense. He saw what no man, not merely no European man, had ever seen before. He had every right to be - he probably was - more amazed than Balboa. 20 THE GREAT CHAIN OF LIFE The draper of Delft was already just short of seventy when he wrote: I had got the aforesaid water taken out of the ditches and runnels on the 30th of August: and on coming home, while I was busy looking at the multifarious very little animalcules a-swimming in this water, I saw floating in it, and seeming to move of themselves, a great many green round particles, of the bigness of sand-grains. When I brought these little bodies before the microscope [actually a single very small lens which he had ground himself and fixed between two perforated metal plates] I saw that they were not simply round, but that their outermost membrane was everywhere beset with many little projecting particles, which seemed to me to be triangular, with the end tapering to a point: and it looked to me as if, in the whole circumference of that little ball, eight such particles were set, all orderly arranged and at equal distances from one another: so that upon so small a body there did stand a full two thousand of the said projecting particles. This was for me a pleasant sight, because the little bodies aforesaid, how oft soever I looked upon them, never lay still; and because too their progression was brought about by a rolling motion.... Each of these little bodies had enclosed within it 5, 6, 7, nay some even 12, very little round globules, in structure like to the body itself wherein they were contained. There is no mistaking the fact that what had just swum into Leeuwenhoek's ken was that very original and inventive MAC H I N E R Y FOR E VOL UTI 0 N 21 organism, Volvox. Through hundreds of millions of years it had waited in countless places for man to become aware of its existence and, ultimately, to guess how important a step it had taken in the direction of both consciousness and that curiosity which was leading the Dutch draper to seek out in the ditches of Delft. The 4:4:little projecting particles" are the peripheral cells which enclose the watery jelly in Volvox's interior. The 4:4:5, 6, 7, nay some even 12, very little round globules, in structure like to the body itself" are the vegetative "daughter cells" produced by a sort of virgin birth between the sexual generations, much as in some of the higher plants "offsets" as well as seeds are produced. Nor did Leeuwenhoek's observation stop there: While I was keeping watch, for a good time on one of the biggest round bodies . . . I noticed that in its outermost part an opening appeared, out of which one of the enclosed round globules, having a fine green color, dropped out; and so one after another till they were all out, and each took on the same motion in the water as the body out of which it came. Afterwards, the first round body remained lying without any motion: and soon after a second globule, and presently a third, dropped out of it; and so one after another till they were all out and each took its proper motion. After the lapse of several days, the first round body became as it were, again mingled with the water; for I could perceive no sign of it. In other words Leeuwenhoek saw both the liberation of the daughter colonies and also, though...