The principal results of such experiments have been: the multiplicity of mistakes made, and the difficulty of fixing attention; that is to say, they reveal the weariness, the degree of fatigue, in children.
This gave the alarm! Old-fashioned pedagogy was concerned solely with what children ought to do. The idea that their nervous energies might be impaired was first called into being by the warning note of science.
Researches into the causes of fatigue became more and more frequent, and coupled with such researches was the less immediate enquiry as to how fatigue could be "combated" or "alleviated." All the factors relating to the question were studied: age, sex, the degree of intelligence, the type of individual, the influence of the seasons, the influence of the various times of the day, of the various days of the week, of habit, intervals of relaxation, interest, variety of work, the position of the body, and, finally, position in reference to the cardinal points.
Science is confronted by a mass of unsolved problems.—The outcome of all these researches is a growing mass of unsolved problems. It has not been established whether males are more easily fatigued than females; whether the intelligent are more subject to fatigue than the unintelligent. With regard to the individual type, Tissié's conclusion seems to be the most noteworthy: "Each individual becomes fatigued or not according to his degree of will." In connection with the seasons it appears that fatigue increases from the first to the last day of school, but it is uncertain whether this is due to the influence of the seasons, or whether, as Schuyten affirms, the scholar's gradual exhaustion is due to the scholastic system. With regard to the time of day, "it is still a question whether the fatigue produced is less when the pupil works spontaneously, but this problem is a difficult one to solve." The days of the week when fatigue is least evident are Monday and Friday, but researches made in this connection are not definitive; as to habit, intervals of rest, interest: "in connection with these factors which are antagonistic to fatigue, it has been questioned whether they actually diminish fatigue, or merely cloak it, but no decision has been reached." A great variety of interesting researches have been made into the question of change of work with identical results—namely, that frequent change of work causes greater fatigue than continuous work of one kind, and that a sudden interruption is more fatiguing than persistence. The following experiment (quoted by Claparède) was made by Schultze: one day the girls were required to add up figures for twenty-five minutes, and then to copy out passages for another twenty-five minutes. Another day they performed the same work, but it was differently divided; they had to add for fifty minutes and to copy for another fifty minutes. Now these last tests gave results infinitely superior to the first. And yet it is well known that, in spite of such results, constant interruption and change of work are commonly practised in schools, as part of a scientific plan for combating fatigue.
One of the researches directly relating to schools is that of the ponogenic co-efficient of the various subjects of instruction, that is to say, of the degrees of fatigue induced by these. Wagner is of opinion a priori that one hundred, the maximum co-efficient, must be assigned to mathematics; in this case, we should get the following ponogenic co-efficients in schools, for each subject:
| Mathematics | 100 |
| Latin | 91 |
| Greek | 90 |
| Gymnastics | 90 |
| History and Geography | 85 |
| French and German | 82 |
| Natural History | 80 |
| Drawing, Religion | 77 |
We may note the arbitrary and surprising manner in which such results are established; nevertheless, in the name of "experimental science" it is possible to make such deductions as the following:
"It would be interesting to enquire if the order of the ponogenic co-efficients varies with the age of the children, which would enable us to know on the one hand when the brain is best fitted for the study of any particular subject and when therefore it would be most judicious to make it predominate in the program; on the other hand, it would help us in the arrangement of the daily time-table; we should take, if possible, the most fatiguing subjects at the beginning of the day" (Claparède, op. cit.).
Another order of recent researches is that made into the toxines produced by fatigue; Weichardt succeeded in isolating these toxines, and in fabricating anti-toxines with which he experimented successfully on rats. The experiments were also repeated in a clinic. With regard to the appearance of the toxines, it was found that they were abundantly produced during the performance of "wearisome" work, whereas there were only traces of them to be found when the work was "interesting."