This doctrine of prime matter and form, which the scholastics adopted and adapted from the Greeks, and especially from Aristotle, cannot fail to be of interest even to modern scientists. According to it, prime matter was an indeterminate something which made up the underlying substratum of all material things. Form was the dynamic element which entered into the composition of matter and made it exhibit its specific qualities. We have heard much of ionization in recent times, and in many ways this would remind one even only slightly familiar with the old scholastics, of their theories of form entering into matter. Prime matter was supposed to be absolutely without distinguishing characteristics of its own. It was indifferent, and had no influence on other material unless when associated with form. Form was the dynamic and energizing element. This, of course, still remains in the realm of theory; {312} but it is interesting to realize that in the olden time they theorized about the constitution of matter at the universities of the thirteenth and fourteenth centuries just as we do now, and most surprisingly came to conclusions quite like ours. Their thoughts not only concerned the same subject, but were worked out in the same way. It is idle to say that they knew nothing about it and hit on their theory by chance. As a matter of fact, they knew very little, if any less about it than we do, for our ignorance on this subject is monumental, and they anticipated our latest thinking by seven centuries. Many have been the divagations of thought since that time, but now we return to their conclusions. It is chastening to the modern mind, so confident of the advances that have been made by these latter generations, "the heirs of all the ages in the foremost files of time," to find that we are so little farther on in an important problem than these men of the thirteenth century.