A Glimpse of Incomprehensibles 



By George W. Corner 



Director, Department of Embryology 

 Carnegie Institution of Washington 



One of the most interesting projects now under way at our 

 laboratory is an experimental study of the behavior of uterine muscle. 

 Dedicated as we are to the study of embryology, we are bound to 

 consider the enviromnent in which the embryo lives, and in particular 

 that remarkable muscular organ, the uterus, in which every one has 

 his first home. A visitor who steps into the rooms of Dr. Arpad 

 Csapo, the leader of this particular research, sees him facing a mass 

 of apparatus, tubing and Avires, all of which is focused upon a small 

 vial housing a strip of rabbit's uterus, three centimeters long. This 

 bit of living tissue is kept at body temperature in physiological salt 

 solution. It is supplied with oxygen and with energy in the form of 

 dextrose. Its environment is thus made as much as possible like that 

 within the intact animal. One end of the strip is fastened to a lever, 

 so that when it contracts, as any involuntary muscle will do of its own 

 accord when so prepared, its rhythmic contractions are recorded on a 

 drum. Watching the lever move up and down, watching the muscle 

 itself shorten and then relax, the fascinated observer realizes with a 

 start that what he is watching is an engine, as much an engine as 

 those which run our motorcars. Like them it has its own firing sys- 

 tem by which the energy on which it operates is turned into mechan- 

 ical work b}^ a kind of explosion. Dr. Csapo chooses to supplant this 

 natural "spark-plug" mechanism by mild electrical shocks from a 

 mechanical timer; thus gaining somewhat smoother timing, he finds 

 that he is indeed running an engine in the most literal sense. The 

 experiment becomes quantitative, like an engineer's test of any steam 

 or gasoline engine. The energetics of operation can be calculated. 

 The work done is precisely related to the amount of contractile pro- 

 tein in the sample and of the fuel used. The strength of the contrac- 



^ Reprinted by permission from the American Scholar, vol. 23, No. 3, Summer, 

 1954. 



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