description of testicular tubules, the efferent ducts, and corpora lutea. De Graaf may have been the first to understand the reproductive function of the Fallopian tube, described the hydrosalpinx, linking its development to female infertility. De Graaf also invented a practical syringe, described in his third treatise. Graafian follicles His eponymous legacy are the Graafian (or ovarian) follicles. He himself pointed out that he was not the first to describe them, but described their development. From the observation of pregnancy in rabbits, he concluded that the follicle contained the oocyte, although he never observed it. The mature stage of the ovarian follicle is called the Graafian follicle in his honor, although others, including Fallopius, had noticed the follicles previously (but failed to recognize its reproductive significance). The term Graafian follicle followed the introduction of the term ova Graafiana by Albrecht von Haller who like De Graaf still assumed that the follicle was the oocyte itself, although De Graaf realized the ovum was much smaller. The discovery of the human egg was eventually made by Karl Ernst von Baer in 1827. De Graaf's contemporary Jan Swammerdam confronted him after his publication of DeMulierum Organis Generatione Inservientibu and accused him of taking credit of discoveries he and :fr:Johannes van Horne had made earlier regarding the importance of the ovary and its eggs. De Graaf issued a rebuttal but was affected by the accusation of plagiarism. Female ejaculation De Graaf described female ejaculation and referred to an erogenous zone in the vagina that he himself linked with the male prostate; this zone was later reported by German gynecologist Ernst Gräfenberg and named after him as the Gräfenberg Spot or G-Spot. Further, De Graaf described the anatomy of the testicles and collected secretions of the gall bladder and the pancreas. Weaknesses Despite his contributions, De Graaf made a number of errors in addition to believing that the ovum was the follicle. He never actually consulted the ancient texts but merely repeated the accounts of others compounding their inaccuracies. Because he observed rabbits rather than humans, he assumed fertilization took place in the ovary. He believed that the seminal vesicles stored spermatozoa. He was not yet aware of the presence of spermatozoa as such; these were discovered just after his death by the Amsterdam student Johannes Ham, using the microscope of Antonie van Leeuwenhoek. Based upon his rabbit experiments and the description of ectopic pregnancy