As will be seen from this passage, Cusanus had many more ideas than merely the accurate estimation of the pulse frequency when he suggested the use of the water-clock. Evidently the thought had come to him that the specific gravity of the substances, that is, their weight in comparison to the weight of water, might be valuable information. Before his time, physicians had depended only on the color and the taste of the urine for diagnostic purposes. He proposed that they should weigh it, and even suggested that they should weigh, also, the blood, I suppose in case of venesection, for comparison's sake. He also thought that the comparative weight of various roots, stems, leaves, juices of plants might give hints for the therapeutic uses of these substances. This is the sort of idea that we are apt to think of as typically modern. Specific gravities and atomic weights have been more than once supposed to represent laws in therapeutics, which so far, however, we have not succeeded in finding, but it is interesting to realize that it is nearly five hundred years since the first thought in this line was clearly expressed by a distinguished thinker and scientific writer. There are many interesting expressions in Cusanus' writings which contradict most of the impressions commonly entertained with regard to the scholars of the Middle Ages. It is usually assumed that they did not think seriously, but speculatively, that they feared to think for themselves, neglected the study of nature around them, considered authority the important source of knowledge, and were as far as possible from the standpoint of modern scientific students and investigators. Here is a passage from Nicholas, on knowing and thinking, that might well have been written by a great intellectual man at any time in the world's history, and that could only emanate from a profound scholar at any time. "To know and to think, to see the truth with the eye of the mind, is always a joy. The older a man grows the greater is the pleasure which it affords him, and the more he devotes himself to the search after truth, the stronger grows his desire of possessing it. As love is the life of the heart, so is the endeavor after knowledge and truth the life of the mind. In the midst of the movements of time, of the daily work of life, of its perplexities and contradictions, we should lift our gaze fearlessly to the clear vault of heaven, and seek ever to obtain a firmer grasp of and a keener insight into the origin of all goodness and beauty, the capacities of our own hearts and minds, the intellectual fruits of mankind throughout the centuries, and the wondrous works of nature around us; at the same time remembering always that in humility alone lies true greatness, and that knowledge and wisdom are alone profitable in so far as our lives are governed by them."