True, it would appear that to-day a way of escape may be offered by the discovery of the anti-toxine for fatigue. "Just think!" exclaims Claparede, "a serum against fatigue. How valuable this would be!" From this point of view, I should say that the ponogenic co-efficients might find a more practical and rational application than that of the revelation of "programs"; indeed these co-efficients indicating the production of toxines would appear destined to determine the dose of anti-toxine necessary to nullify the evil effects resulting from each different subject of instruction. In the not far distant future, when these auxiliary sciences of the school and pedagogy shall have made due progress, we shall perhaps see, side by side with the orthopaedic ward, a physio-chemical clinic, where every evening the pupils, as they leave the beneficent suspensory apparatus which counteracts injury to their skeletons, may enter with a kind of ponogenic prescription regulated by the teaching they have undergone, and receive an injection which will deliver them from the poisonous effects of fatigue! This reads like an irony of the worst kind, perhaps; but this is not the case. Where the orthopaedic institution is already an accomplished fact, we may very soon see the chemical clinic established. If a problem of liberty is to be solved with machines, and if a problem of justice is to be regarded from the chemical point of view, similar consequences will be the logical end of sciences developed upon such errors. It is obvious that a real experimental science, which shall guide education and deliver the child from slavery, is not yet born; when it appears, it will be to the so-called "sciences" that have sprung up in connection with the diseases of martyred childhood as chemistry to alchemy, and as positive medicine to the empirical medicine of bygone centuries. I think it will be of interest here to record the impressions of a person who, leaving the field of mathematics, entered upon the study of biology and experimental psychology. It is an account of a young English engineer, who had evidently mistaken his vocation, and who, after studying my method for two years, returned to the universities of his own great country as a student of biology. This is his opinion of experimental psychology: