EFFECTS OF SCHO OL LIFE 2 5 9 



olism could hardly fail to affect unfavorably that organ most con- 

 cerned in the overpressure — the brain itself. 



Binet and Schuyten (2), by carefully weighing the quantities of 

 food consumed by school children in the different months of the school 

 year have been able to show that the child's appetite deteriorates as the 

 school year proceeds. The exact causes of such deterioration are very 

 complex and difficult to disentangle, but the basis, at least, for an ex- 

 planation is to be found in such investigations as those of W. B. 

 Cannon, Pavlow and others on the physiology of digestion. 



Data of this kind lead us to infer that the nervous stimulation in- 

 volved in excessive mental work produces its injury through such re- 

 flex effects as those upon the nutritive processes. Graziani, however, 

 has raised the question whether in addition there may not be unfavor- 

 able influences more direct than this explanation assumes. He be- 

 lieves there are two such influences : (a) Imperfect oxygenation of the 

 blood and incomplete elimination of carbon dioxide due to the super- 

 ficial respiration proved by Mosso, Macdonald, Bush, Obici and others 

 to result from application to mental tasks; and (b) an immediate ef- 

 fect upon the chemical composition of the blood corpuscles due to the 

 accumulation of fatigue products resulting from mental work (5). 



In order to test the latter theory, Graziani subjected 18 university 

 students and 17 children of ten to twelve years of age to blood tests 

 before and after the preparatory period for school examinations. The 

 tests involved three determinations : the number of red corpuscles, the 

 relative proportion of hemoglobin which they contained, and their 

 power of resistance. In regard to the number of corpuscles, no con- 

 stant differences were found either with university students or with 

 children. The proportion of hemoglobin, however, showed a decided 

 decrease, amounting to an average of 10 per cent, with the students and 

 to nearly that much with the children. The effect upon the power of 

 resistance of the red corpuscles was much the same as other investiga- 

 tors had shown to result from certain poisons. Graziani, therefore, con- 

 cludes that in all probability mental work produces a toxin which 

 brings about an immediate change in the chemical and functional prop- 

 erties of the blood. 



To try this theory still further he subjected himself and a twelve- 

 year-old boy to the same kind of blood examinations, except that in this 

 experiment the blood tests were separated only by a number of hours 

 of strenuous mental work instead of by many weeks, as was the case in 

 the earlier experiment. Here, again, the decrease of homoglobin was 

 marked, amounting on an average to 7.5 per cent, with Graziani him- 

 self and to 8 per cent, with the boy. Graziani believes that the under- 

 lying cause of school anemia, with its alterations of metabolism and its 

 imperfect oxygenation of the blood, is to be sought in the influence of 

 excessive accumulations of toxic products of fatigue. 



