LIFE AND THE CELL 47 



itself. The seventeenth-century microscopy was necessarily limited by 

 the imperfections of the early instruments, and still more by the state of 

 the allied sciences at the time. But it was, none the less, an era of high 

 adventure in natural history, for the lens, however faulty, gave to all 

 greatly inquisitive minds the first rapturous look at the wonderworld of 

 structure. Without that glimpse, steriHty would have fallen upon further 

 inquiry, so that the microscope seems to have come not a moment too soon 

 in the history of natural science. 



If I were writing the history of biology, I would tell how the century 

 had been electrified at its opening by Harvey's announcement of the cir- 

 culation of the blood, and how others applied themselves to the great un- 

 finished business of measuring that mortal tide. When Malpighi turned 

 his lens upon the structure of the lung, he saw for the first time why it is 

 that man draws breath. When Leeuwenhoek peered through his home- 

 contrived microscope, he found the corpuscles of the life stream, that no 

 eye had seen before — and was tickled in his bourgeois soul to set Swam- 

 merdam right about them. The heart, the brain, the glands, the nerves, 

 every organ of the human and his fellow vertebrates, became subject to 

 intensive scrutiny. And that scrutiny for the first time revealed the func- 

 tions of the organs. It is almost impossible for me to believe it, but it is 

 true that not so long ago men did not know that the brain was the seat of 

 thought; some believed that it cooled the blood. No one ever thought 

 more nobly than Plato, but he never guessed what he was thinking with. 

 He had no idea that whatever else thought may be, it is also a physical 

 process, like digestion. So biology was at last founded upon the structure 

 of life itself, and natural history, which is the outdoor view of biology, 

 was tethered at last to physical realities. 



Young Jan Jacobz Swammerdam impresses us now as the greatest bi- 

 ologist of his age, and once more I am going to slight many accomplish- 

 ments and tell my story in terms of what Swammerdam learned of the 

 cryptic, multiplex and jfantastical insect world. 



For the insects constitute an exception to almost everything you can 

 say about the rest of the animal kingdom. You no sooner think that you 

 have established a law, discovered a fundamental plan of animal architec- 

 ture, or learned a secret of function, than you find some long-faced grass- 

 hopper sneering denial at you. The very stuff of which the insects are 

 made is not like ours. They are not built of bones, but encased in chitin. 

 Chitin is the horn of the rhinoceros beetle, the wing of the dragonfly, the 

 sting, the eye, the armor, the hairs, the antennae, the very thread on which 

 the spider escapes you. Nothing will so permanently revise your biological 

 outlook as to discover how different an animal may be from yourself and 

 still in its own environment be a king. The insect, for instance, has what 

 may be called a brain, but how differently constituted. Its sensory receiv- 

 ing organs are scattered, not concentrated into a federal government, so 



