Then there was astronomy, metaphysics, theology, music and law and medicine. The science of law was developed and, above all, great {108} collections of laws made for purposes of scientific study. Of astronomy every one was expected to know much, of medicine we shall have considerable to say hereafter, but in the meantime it is well to recall that these mediaeval centuries maintained a high standard of medical education and brought some wonderful developments in the sciences allied to medicine and above all in their applications to therapeutics. Surgery never reached so high a plane of achievement down to our own time, as during the period when it was studied so faithfully and developed so marvellously at the mediaeval universities. It was inasmuch as a knowledge of physics was needed for the development of metaphysics that the mediaeval schoolmen devoted themselves to the study of nature. They turned with as much ardor and devotion as did Herbert Spencer in the nineteenth century, to the accumulation of such information with regard to nature as would enable them to draw conclusions, establish general principles and lay firm foundations for reasonings with regard to the creature and the Creator. It is, above all, this phase of mediaeval teaching work, of the schoolmen's ardent interest that is misunderstood, often ignored and only too frequently misrepresented in the modern time. For instance, in the discussion of the status of matter in the universe the scholastics and notably Thomas Aquinas had come to the conclusion that matter was absolutely indestructible. He {109} even went so far as to say that man could not destroy it, and God would not annihilate it. _Nihil omnino in nihilum redigetur_--nothing at all will ever be reduced to nothingness, was his dictum as the conclusion of a course of lectures on this subject. He saw the changes in matter all round him that were supposed to be destructive, the burnings, the vaporizations, the solutions, the putrefactions and all the rest, but he knew that these only brought changes in matter and not destruction of the underlying substance. For him, as for all the scholastic philosophers, matter was composed of two principles, as they were called. One of these was prime matter and the other form. To prime matter, one of these, matter or substance owed all its negative qualities, inertia and the like. To form, the dynamic element or principle, it owed all its individuating qualities. Prime matter was the same in all things. Form was the energy or bundle of energies, the dynamic principle, as we have said, which entering into prime matter, made the different kinds of matter that we speak of.