924: SPECIAL PHYSIOLOGY. 



and by the increased respiration and circulation, rather than by the direct 

 waste of the voluntary muscles. (Yoit, Bischoff.) 



Lastly, the experiments of Dr. Edw. Smith prove, on the other hand, that 

 the production of carbonic acid does increase, strictly in accordance with the 

 exercise taken. During sleep, the quantity exhaled in an hour was, in his own 

 case, 19 grammes ; whilst lying down before sleep, 23 ; in a sitting posture, 

 29 ; whilst walking two miles an hour, 70.5 ; in walking three miles an hour, 

 100.6 ; and upon the treadwheel, lifting his body, 28.65 feet in a minute, as 

 much as 189.6 grammes per hour. 



The recent observations of Fick and Wislicenus, on the results of a certain 

 amount of work performed by themselves, also point to the conclusion, that 

 muscular effort, on a non-nitrogenous diet, does not increase the quantity of 

 urea excreted from the body ; moreover, they conclude that the oxidation of 

 the quantity of albuminoid substance, or plastic nitrogenous material, which 

 would correspond with the urea and other nitrogenous compounds then ex- 

 creted, does not yield sufficient potential energy to perform the work accom- 

 plished. The mechanical work undertaken by them, was the ascent of the 

 Faulhorn, a mountain in the Bernese Oberland. From the middle of the day 

 before, until the ascent was completed, no albuminoid food was taken, so that 

 no excess, or luxus consumption, might interfere with the experiment. During 

 11 hours of the night previous to the ascent, the quantities of urea excreted 

 by them respectively, were by Fick, 12.5, and by Wislicenus, 11.75 grammas. 

 During the 7 hours and 40 seconds occupied in the ascent, or work-hours, i. e. , 

 from 10 rnin. past 5 A.M. to 20 min. past 1 P.M., the quantities were 7. and 

 6.7 grammes. During the next 5 hours and 40 min. of rest, or after work, in 

 which an abundant meal of meat was consumed, the quantities were 5. and 

 5.1 grammes. The quantity of urea excreted per hour was, therefore, not in- 

 creased during exercise on a non-nitrogenous diet. In determining the relation 

 between the quantity of albuminoid substance decomposed, and the mechanical 

 work performed, they take into account not only the urea, but the whole nitro- 

 gen eliminated in a more or less oxidized form, and they find that this, dur- 

 ing the actual period of work, would represent in F. 22.098, and in W. 20.89 

 grammes of albumen. The minute trace of nitrogen given off from the skin 

 is neglected, and so is the larger quantity contained in the faeces, because it 

 passes off in almost unoxidized compounds. The possible retention in the 

 system of some partially oxidized albuminoid substances, such as creatin, is 

 admitted ; but to compensate for this they add a quantity of albumen, equal 

 to the nitrogen excreted in the period of after work, making the respective 

 totals, 37.17 and 37. grammes of albumen oxidized. The heat given out by 

 the oxidation of these quantities in the body, is unknown ; but from avowedly 

 imperfect data, and making the fullest possible allowance, they conclude that 

 the energy obtainable from its oxidation might be for F. 250,000, and for W. 

 249,000 heat-units ; giving respectively 106,250, and 105,825 met. kils. of me- 

 chanical power. Now the chief work actually performed by them, was lifting 

 the weights of their bodies, as clothed, through the height of the mountain ; 

 this is measurable by multiplying the former by the latter. Thus F. exerted 

 a force of 66 kil. X 1956 metres = 129, 096 met. kils., and W. a force of 76 kil. 

 X 1956 metres =148, 696 met. kils. ; if to this be added the internal work of 

 respiration and circulation, the totals are, for F. 159,637, and for W. 184,287 

 met. kils. These results show, therefore, that the mean work performed, in 



Proportion to the power derivable from the oxidized albumen, was as 3 to 2. 

 t is well known, however, that much other work is performed in the exer- 

 cised body, which does not contribute directly to the external work performed ; 

 and Heidenhain has computed that only one-half the energy of the force-gen- 

 erating processes, is really used as work. Hence, double the amount of work 

 was actually performed in the bodies of F. and W., or 319,274 and 368,574 

 met. kils. ; in other words, the ratio of work performed to the power derivable 

 from the consumption of albuminoid substances in the body, was as 3 to 1. 

 Since, therefore, it is impossible for the oxidized albumen to be the sole and 

 exclusive source of the power manifested in the work of the body, to which it 

 can contribute so little, they conclude that the oxidation of non-nitrogenous 

 substance must yield, at least, the larger proportion of the force required, not 



