O'SIIEA — ASPECTS OF MENTAL ECONOMY. 75 



promote cither muscular or mental action ; and those adapted to 

 supply physical power in Largest measure are not in all cases the 

 ones from which to gain cerebral energy most advantageously, as 

 will be demonstrated more fullv later. It should be noted here, 

 however, that we say just the ones, for in some degree the energy 

 of the entire organism may on occasion be drawn upon for the 

 maintenance of either mental activity, motor activity, or tem- 

 perature. This is indicated in the fact that arduous manual 

 labor lessens the vigor, keenness, and duration of intellectual 

 processes, 1 and reduces the temperature of the body. And in 

 the same way intense and long continued mental application 

 reduces the power of motor execution, 2 and, as in muscular 

 labor, makes heavy demands upon the calorific condition of the 

 system. 3 Spencer 4 called attention to this some time ago, and 

 insisted that excessive brain work was causing physical dete- 

 rioration in the English people. Mosso 5 maintains that severe 

 brain work makes so great a demand upon the energies of the 

 body that the muscles sacrifice a part of their albuminous con- 

 stituents that mental activity may be sustained. 



And yet there is a limit to the convertibility of the energies 

 of the organism. One may be in good flesh and yet be under- 

 nourished nervously. Warner, 6 in his inspection of the school 

 •children of London, has frequently found instances where there 

 was every evidence of adequate bodily nourishment, and yet 

 nerve signs revealed a depleted condition of the brain. A few 

 years ago there came under my observation in the city of Buf- 

 falo two children who gave their teachers and parents much 

 trouble on account of their irritability and the slow progress 

 they made in their studies. They appeared outwardly to be 

 well nourished ; but finally upon expert examination it was 



1 Curtis, Pedagogical Seminary, Vol. VI. VI, No. I, p. 78, quotes Mosso as saying 

 that he has several times climbed to the top of Mount Blanc, but he can remem- 

 ber nothing of the view. He has a friend who has to write down his impressions 

 ■on his way up or he can retain nothing. 



2 Mosso loc. cit. 



s See an Instance of lack of sleep causing marked fall in temperature. Peda- 

 gogical Seminary, Vol. VI, No. 1, p. 81. 

 ^Education, p. 260 et seq. 

 8 Loc. cit. 

 'Mental Faculty, pp. 79-80. 



