The teaching of Mendel strikes at the root of two or three difficult and vital problems. It presents a new conception of the proximate mechanism of heredity. The hypothesis of heredity that it suggests will focus our attention along new lines, and will, I believe, arouse as much discussion as Weissmann's hypothesis, and it is probable that it will have a wider influence. Whether it expresses the actual means of heredity or not, it is yet much too early to say. But the hypothesis (which Father Mendel evolved in order to explain the reasons for his law as he saw them) is even a {201} greater contribution to science than the so-called Mendel's Law as to the numerical results of hybridization. In the general discussion of evolution Mendel's work will be of the greatest value because it introduces a new point of view, challenges old ideas and opinions, gives us a new theory for discussion, emphasizes the great importance of actual experiments for the solution of many questions of evolution, and then forces the necessity for giving greater attention to the real characters and attributes of plants and animals than to the vague groups that we are in the habit of calling species. It is very evident that a man of whose work so many authorities are agreed that it is the beginning of a new era in biology, and especially in that most interesting of all questions, heredity, must be worthy of close acquaintance. Hence the present sketch of his career and personality, as far as they are ascertainable, for his modesty, and the failure of the world to recognize his worth in his lifetime, have unfortunately deprived us of many details that would have been precious. Gregor Johann Mendel was born 27 July, 1822, at Heinzendorf, nor far from Odrau, in Austrian Silesia. He was the son of a well-to-do peasant farmer, who gave him every opportunity of getting a good education when he was young. He was educated at Olmutz, in Moravia, and after graduating from the college there, at the age of twenty-one, he entered as a novice the Augustinian Order, beginning his novitiate in 1843 in the Augustinian monastery Königen-kloster, in Altbrünn. He was very successful in {202} his theological studies, and in 1846 he was ordained priest. He seems to have made a striking success as a teacher, especially of natural history and physics, in the higher Realschule in Brünn. He attracted the attention of his superiors, who were persuaded to give him additional opportunities for the study of the sciences, particularly of biological science, for which he had a distinct liking and special talents.