Theories and Experiments 291 



Then basing his conclusion on recent physiological data, he con- 

 sidered that the work of ascent uses up the reserve of ternary 

 materials contained in the blood and the tissues, and results in the 

 muscular exhaustion. 



I shall quote this noteworthy passage verbatim: 



It is probable that during the first hours of the ascent, the muscu- 

 lar work consumes the non-nitrogenous substances immediately avail- 

 able either in the muscular substance or in the blood. 



What replacement can compensate for the effect of so great an 

 expenditure? It can take place in only two ways: either the chylif- 

 erous vessels bring into the circulatory stream new elements supplied 

 by the digestion, or the organism absorbs and draws again into the 

 circulation the elements of the subcutaneous adipose tissue. This last 

 point is so certain that working hard and eating little is a means of 

 getting thin that is well known to everybody. The first of these re- 

 placements can be made quite quickly; the second, if we judge by the 

 phenomena of absorption which we often witness, can take place only 

 much more slowly. 



It is probable that the absorption of the adipose tissue to be used 

 as a combustible in the work of ascent is a phenomenon too slow to 

 compensate satisfactorily for the expenditure caused by the work of 

 someone ascending without stopping. 



Therefore a moment must come whea, if the climber does not eat, 

 the available combustible material keeps diminishing and can be only 

 partly replaced by absorption. This effect will be produced most 

 easily when after work of several hours the climber approaches a steep 

 grade which he wishes to climb too quickly, so that there is a still 

 greater disproportion between the work performed and the time used 

 in performing it. (P. 77.) 



Therefore, according to M. Dufour, it is very easy to explain: 



a. The importance of rest, because during rest there is no ex- 

 penditure whereas replacement continues. 



b. The fact that after rest, the quantity of work easily performed 

 is obviously proportional to the duration of the rest; for the same 

 reason as above. 



c. The fact that, to anyone who has mountain sickness, any new 

 effort, such as stooping or using the arms, becomes painful. (See 

 H.-B. de Saussure.) 



d. The fact that mountain sickness seems to attack plump persons 

 more than thin persons, because the former produce, on an equal 

 ascent, a much larger number of kilogram-meters of work. The fact 

 that they have in the adipose tissue a deposit of combustible material 

 is without importance here, for very thin persons always have a suffi- 

 cient adipose membrane to supply the work of ascent as it generally 

 appears. 



f. Finally, the fact that a means of avoiding mountain sickness is 

 to eat often, that is, to furnish materials not by way of resorption, but 

 by way of digestion and absorption. (P. 78.) 



