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POPULAR SCIENCE MONTHLY. 



ant. Moreover, such meteors must or- 

 iginate 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 as- 

 sumptions as to the existence of the 

 cosmical centers of emission, primitive 

 velocity and direction. 



Without seeing M. von Niessl's or- 

 iginal 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 possi- 

 ble to make reasonable assumptions as 

 to velocity, etc., that will account for 

 all the observed phenomena. A geo- 

 metrical explanation of stationary radi- 

 ants 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. 



THE UTILIZATION OF FOOD AND 

 ALCOHOL IN THE HUMAN BODY. 

 Widespread 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 num- 

 ber 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- 

 Eosa respiration calorimeter. It pre- 

 sents additional data bearing upon th« 

 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 practical- 

 ly attained. Upon the addition to the 

 basal ration of an amount of alcohol or 

 sugar furnishing approximately 500 cal- 

 ories of energy per day, it was found 

 that the body appeared to store an. 

 amount of fat having practically an iso- 

 dynamic value with the alcohol or sugar 

 eaten. It is doubtful whether all the 

 energy in the sugar was actually avail- 

 able to the body, some los3 being sus- 

 tained in transferring the sugar from 

 the alimentary canal into the circula- 

 tion. Assuming 98 per cent, of the en- 

 ergy of the sugar to be actually avail- 

 able 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 experi- 

 ments 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 fea- 

 tures 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 experi- 

 ments to study further the metabolism 

 of different classes of nutrients and the 

 relative replacing power of the energy 

 as furnished by different materials. 



