To prevent the dangers that may arise from the unskilful drawing of blood, let none open a vein but a person of experience and practice. There are three sorts of people you must not let draw blood: first, ignorant and inexperienced pretenders. Secondly, those who have bad sight and trembling hands, whether skilled or unskilled. For when the hand trembles, the lancet is apt to startle from the vein, and the flesh be thereby damaged, which may hurt, canker, and very much torment the patient. Thirdly, let no woman bleed you, but such as has gone through a course of midwifery at college; for those who are unskilful may cut an artery, to the great damage of the patient. Besides, what is still worse, those pretended bleeders, who take it up at their own hand, generally keep unedged and rusty lancets, which will prove hurtful even in a skilful hand. Accordingly, you ought to be cautious in choosing your physician: a man of learning knows what vein to open for each disorder; he knows how much blood to take as soon as he sees the patient; and he can give you suitable advice concerning your disorder. [Illustration: FORM OF A MALE CHILD IN THE WOMB. EXPLANATION. A The uterus, as stretched to near its full extent, containing the _fœtus_ entangled in the _funis_.—B. B. The superior part of the _ossa ilium_.—C. C. The _actebula_. D. D. The remaining posterior parts of the _ossa ischium_.—E. The _coccyx_.—F. The inferior part of the _rectum_.—G. G. The _vagina_ stretched on each side.—H. The _os uteri_, stretching to its full extent.—I. I. Part of the _vesica urinaria_.—K. K. The _placenta_ at the superior and posterior parts of the _uterus_.—L. The _Membranes_.—M. The _funis umbilicalis_. ] ARISTOTLE’S BOOK OF PROBLEMS, WITH OTHER ASTRONOMERS, ASTROLOGERS, AND PHYSICIANS, CONCERNING THE STATE OF MAN’S BODY.