Page:Popular Science Monthly Volume 58.djvu/562

554. Moreover, such meteors must originate in certain fixed emissive centers in the stellar regions (beyond the solar system). The phenomena for certain aerolites whose fall has been observed are accounted for by reasonable assumptions as to the existence of the cosmical centers of emission, primitive velocity and direction.

Without seeing M. von Niessl's original paper it is impossible to give more than the foregoing brief report. It is obvious that if we assume a set of centers of emission exterior to the solar system, and suppose that they send out swarms of meteors which, in time, reach the solar system, it is possible to make reasonable assumptions as to velocity, etc., that will account for all the observed phenomena. A geometrical explanation of stationary radiants can be had in this way. It is not yet possible to say whether there is sufficient physical evidence to make the existence of such extra-solar emissive centers probable. All that can now be done is to report this essay towards a physical explanation of a very puzzling phenomenon.

interest has been taken in the results reported by Prof. W. O. Atwater on the food value of alcohol. These alcohol experiments constitute a part of a series of experiments on the utilization of food in the human body which have been in progress for a number of years. A technical description of a number of them forms a part of a bulletin by Professor Atwater et al. on 'The Metabolism of Matter and Energy in the Human Body,' just issued by the United States Department of Agriculture. The bulletin describes in detail fourteen experiments carried on with human subjects in the Atwater-Rosa respiration calorimeter. It presents additional data bearing upon the metabolism of matter and energy in the human body under conditions of rest and work, the conservation of energy under these conditions, the action of the ordinary food nutrients in the body, and the effect of muscular work upon nitrogen metabolism.

The aim in these experiments was to furnish the subject with approximately the quantity of nitrogen, carbon and energy in the basal ration that would be required to keep him in nitrogen and carbon equilibrium. This was practically attained. Upon the addition to the basal ration of an amount of alcohol or sugar furnishing approximately 500 calories of energy per day, it was found that the body appeared to store an. amount of fat having practically an isodynamic value with the alcohol or sugar eaten. It is doubtful whether all the energy in the sugar was actually available to the body, some loss being sustained in transferring the sugar from the alimentary canal into the circulation. Assuming 98 per cent, of the energy of the sugar to be actually available to the body, it is calculated that this would give 505 calories of available energy furnished by the sugar, and 477 calories of extra fat stored by the body, as compared with the preceding experiments upon the basal ration.

The close agreement between the quantities of heat actually determined and the theoretical amounts furnished by the materials actually oxidized in the body is one of the interesting features of the experiments, and indicates the degree of accuracy which has been attained with the apparatus and the methods employed.

An important scientific result of these investigations thus far has been to demonstrate, in a manner which has never been done before, the application of the law of the conservation of matter and of energy in the human body.

The report is largely one of progress. The authors propose in future experiments to study further the metabolism of different classes of nutrients and the relative replacing power of the energy as furnished by different materials.