If one wishes to know the illness from which he is suffering, one must subtract the individual, with his particular qualities: `The author of nature,' said Zimmermann, `has fixed the course of most diseases through immutable laws that one soon discovers if the course of the disease is not interrupted or disturbed by the patient'; at this level the individual was merely a negative element, the accident of the disease, which, for it and in it, is most alien to its essence.