Whether a work, entitled _Midwife's Practice_, by Hugh Chamberlen, 1665, was by the translator of Mauriceau's work, or by his father, must now remain a matter of doubt: it was, however, in all probability by the latter, from what the translator says in his preface, viz. "I designed a small manual to that purpose, but meeting some time after in France, with this treatise of Mauriceau, I changed my resolution into that of translating him." On account of his being attached to the party of James II. he was again obliged to quit England, in 1688, and crossed over to Amsterdam, where he settled, and in five years after succeeded in selling his secret to three Dutch practitioners, viz. Roger Roonhuysen, Cornelius Bökelman, and Frederick Ruysch, the celebrated anatomist. In their hands, and in those of their successors, it remained a profound secret until 1753, when it was purchased by two Dutch physicians, Jacob de Visscher and Hugo van de Poll, for the purpose of making it generally known. It turned out to be a flat bar of iron, somewhat curved at each end: this lever was stated to have been received from Roonhuysen, one of the original purchasers of the Chamberlen secret; but there is no reason to suppose that any such instrument had been communicated by Chamberlen either to him or the others, as we have distinct evidence that both Ruysch and Bökelman possessed _forceps_, the blades of which united at their lower end by means of a hinge and pin. It is known also that Roonhuysen used a double instrument consisting of two blades. The above-mentioned flat bar of iron, commonly called Roonhuysen's lever, was, without doubt, invented after his time, by Plaatman, who received the Chamberlen secret from him. (_Edin. Med. and Surg. Journal_, Oct., 1833.) [Illustration: Chamberlen's Forceps.]