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WM. CAMERON CHUMLEA: Well, the reactance is supposedly produced by some aspect of the membrane acting as a capacitor. Again, the theory is that the current eventually exceeds some magic number there, and it basically overpowers the capacitor effect. However, with the commercial machines, we still recorded reactance values up at over a megahertz. Now, I do not know if that is a function of the quality of the machine or the fact that the body was not doing what it was supposed to be doing.

But what we have found from theory and from using these commercial machines is that they do not always agree. Now, maybe the Hewlett-Packard or some of these more expensive ones would give us the correct answers.

DENNIS BIER: As you mentioned in your presentation, there are a variety of people here who are on the NIH Technology Assessment Conference panel, and I do not want to compete with them.

WM. CAMERON CHUMLEA: Dennis was on the panel.

DENNIS BIER: It was hung up on two things. As opposed to what we heard about this morning, where there was one black box (you have a measurement and you know what it is measuring, and an algorithm, which is a black box), here we have two black boxes. We have the algorithm, in which remains a black box, and then we have a measurement which we do not really know what it is measuring. So we have a lot of theories about what it should be measuring and calculations based on electrical principles in defined physical systems, but until we determine what it is actually measuring on a biophysical basis, we have real trouble understanding what we are doing.

WM. CAMERON CHUMLEA: The report of this panel, if I am correct, will be published in The American Journal of Clinical Nutrition (NIH, 1996) as a special issue some time later this year.

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