[Editorial Note.—This paper and the papers of Drs. Baker and Vecki, which follow it, constitute a symposium on urologic subjects.] It is not the purpose of this paper to discuss the subject of male sterility. The absolute sterilities that follow gonorrheal epididymitis or the orchitis of mumps, or other definite pathologic conditions, are well known and need little amplification. It is not so well known, however, that there are lesser variations in fertility which are more in the nature of functional disorders, and which are therefore more susceptibile of improvement. For some reason or other, physicians have always regarded the fertility of the man as above reproach. It is now beginning to be recognized that the man may be just as much at fault as the woman in accounting for a given sterile marriage; but there still remains the mistaken notion, "Once fertile, always fertile." In other words, there