In the methodical or synoptic table, at the end of the De Backers' work, not only are the subjects well-nigh innumerable, which have their catalogues of authors' names attached to them, but such subjects too are here as might not be expected. Thus "Military Art" has 32 authors' names under it; "Agriculture" 11; "Navy" 12; "Music" 45; "Medicine" 28. To conclude then our History of this Educational Order, we have one synoptical view of it in these twelve or thirteen thousand authors, all of one family. We have much more. This one work "attesting," as De Backer says in his preface, "at one and the same time a prodigious activity and often an indisputable merit," whereof three and a half centuries have been the course in time, and the whole world the place and theatre, is a general record of religion, letters, science, and education, in every country, civilized or barbarous, where the Society of Jesus labored and travelled. And where has it not done so? In many parts of the world it was the first to occupy the field with literary men, who then sent communications to their superiors, or to learned societies, about the manners of different countries, the state of religion there, of letters, science, and education, including reports of their own observations in geography, meteorology, botany, astronomy, mineralogy, etc. Original sources, from which later history in North, South, and Central America is drawing materials, are seen described here as they appeared; so too with regard to Japan, China, Thibet, the Philippine Islands, Hindustan, Syria, as also to-day with respect to the native tongues of the North American Indians. Here the record of published literature, described and catalogued according to date, marks the stages of mathematical and physical science, from the end of the sixteenth century onwards, and of magnetic and electrical researches all through last century; as well as the relationship between the books of Jesuit authors and similar or kindred ones, by persons outside the Society, in different countries and of divers religions. In short, works composed in most of the tongues of the world exhibit the chief periods in universal culture, and the developments elaborated in the civilization of mankind.[143] PART II. ANALYSIS OF THE SYSTEM OF STUDIES CHAPTER X. AQUAVIVA. THE RATIO STUDIORUM. So centralized an Order as the Society of Jesus, which formed its Professors for every country, and sent them from one place to another, undertook, in doing so, to exhibit a definite system of education, of courses, of method. Besides such a unity of method, it professed also a consistent uniformity of doctrine.