J. E. Fischer, M.D. Professor Greep, ladies and gentlemen. It is a great pleasure for me and the participants to be present at this International Meeting of Parenteral Nutri­ tion. This meeting would not have been possible five years ago. At that time we were still arguing about central vs. peripheral routes, efficacy of the tech­ nique, and still getting accustomed to our ability to support patients nutri­ tionally. Within the last five years these discussions, which seem almost futile in retrospect, have been put aside. Both techniques, we know how, work quite well and have their own indications. Having become comfortable with the technique, it is now time to enter the second phase of parenteral nutrition, and that is the differentiation of the technique for the benefit of different patients. Over the next two days we will be discussing several problems which at the present time are central to the entire subject of parenteral nutrition. Is a fat calorie the same as a carbo­ hydrate calorie? What is the effect on protein metabolism of the fat calorie as opposed to the carbohydrate calorie? Are they equivalent? Are'there situations in which one is superior to the other? Perhaps we will find out tomorrow in the panel.