242 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1954 



tions (i. e., isometric tension) can be predicted from the size and 

 physiological state of the muscle sample, and Dr. Csapo has even 

 found a way, by the use of the ovarian hormones, to alter the mechan- 

 ical performance in much the same way as when the pressure of steam 

 supplied to a steam engine or the rate of carburetion of a gasoline 

 motor is changed. 



Thus far I have spoken only of isolated muscle tissue under fully 

 controlled laboratory conditions ; but we know also from very recent 

 experiments by Dr. Brenda Schofield that the whole uterus in the 

 rabbit's body operates on the same principle and would behave as 

 uniformly except that it is affected by other complex regulatory fac- 

 tors, such as the nervous system and the ovarian hormones. 



The nerves of the uterus apparently come into play chiefly for 

 regulatory purposes on critical occasions ; that is to say, the impulses 

 they carry coordinate one part of the uterus with another when the 

 fertilized eggs are to be received and accurately positioned in the 

 uterus, and again when the infants are to be delivered. These nerve 

 impulses are known to consist of ionic reactions ; they and the blood 

 flow that transports carbohydrate fuel to the uterus, in fact all the 

 operative controls, are physicochemical processes. The whole organ 

 must be regarded as a mechanism, no less than the isolated strip, 

 although the intact uterus in situ is of course a more complicated 

 mechanism and less uniform in its activity under experimental 

 observation. 



The investigator, for hours silently watching and controlling these 

 experiments, inevitably asks himself, Is not then the whole rabbit 

 also a mechanism, and if so, why not the man who watches? His 

 muscles and nerves and brain that devised the experiment, his curiosity 

 that asked the questions, the energy that drives him to answer them — 

 is not all this the product of biochemical reactions under fixed laws 

 of the physical world? 



This is an old question, as old as philosophy itself, to which in the 

 past an answer has often been given one way or the other by scientist 

 or theologian. It was put again to me, not long ago, by one of Amer- 

 ica's eminent scholars. This friend of mine, a professor of literature, 

 has a doctor son who works alongside of us; perhaps it was the 

 younger man's enthusiastic talk of biophysics that disturbed the 

 father. Perhaps also the professor, who is expert in the history of 

 eighteenth-century thought, is still irked by the brash statements 

 of mechanistic philosophy given two centuries ago by men like La 

 Mettrie, author of books entitled "Man a Machine" and "Natural 

 History of the Soul." At any rate, he asked me in all seriousness 

 whether the advance of science and particularly of human biology 

 does not threaten to reduce all human activity to physicochemical 



