It remains, then, to see whether there was any diminution of the interest in chemistry after the issue of this decree by John. In the fourteenth century we find the two Hollanduses, probably father and son, whose lives run during most of the century, doing excellent work in science. They frequently refer to the writings of Arnold of Villanova, so that they certainly post-date him. From them altogether, we have some eleven treatises on various chemical subjects. Some of these, especially with regard to minerals, have very clear descriptions of processes of treatment which serve to show that their knowledge was by no means merely theoretical or acquired only from books. Probably before the end of the fourteenth century there was born a man who must be considered the father of modern pharmaceutical chemistry. This was Basil Valentine, the German Benedictine monk, whose best known work is the "The Triumphal Chariot of Antimony." Its influence can be best appreciated from the fact that it introduced the use of antimony into medicine definitely, and that substance continued to be used for centuries, so that it was not until practically our own generation that the true limitations of its usefulness were found. Valentine described the process of making muriatic acid, which he called the spirit of salt, and taught how to obtain alcohol in concentrated form. Altogether, this monk-alchemist, who was really the {137} first of the chemists, left twenty-three treatises, some of them good-sized books, on various subjects in chemistry. [Footnote 18] It does not look, then, as though chemistry was much neglected during the fourteenth and fifteenth centuries. [Footnote 18: For a brief sketch of his career see my Catholic Churchmen in Science. Dolphin Press, Philadelphia. 1906.] One step more in the history remains to be taken, which brings us down to a man who is more familiar to modern physicians--Paracelsus. Paracelsus received his education just at the beginning of the sixteenth century, before the Reformation began. He was not a man, as those who know his character will thoroughly appreciate, to confess that he had received much assistance from others. He does mention, however, that he was helped in his chemical studies by the Abbot Trithemius, of Spanheim; by Bishop Scheit, of Stettbach; by Bishop Erhardt, of Lavanthol; by Bishop Nicholas, of Hippon; and by Bishop Matthew Schacht.