Fifty oocytes were studied with light microscope and electron microscope. The shape of oocyte is round, about 50—100?m in diameter. The nucleus is large and spheroidal in shape. The diameter of the nucleus is 15—20?m. All the oocytes are surrounded by zona pellucida and follicular cells. Call-Exner bodies are seen between these follicular cells. A great number of microvilli are present on the surface of oocytes. The paired membranes of nucleus envelope is clearly seen. There are a lot of nuclear pores on nuclear envelope, about 4,000/mm~2. The nuclear pore complex is disinct. The cytoplasm of oocyte abounds with organelles which are distributed regularly. The cristae of mitochondria are short and scarety. The mitochondrial matrix becomes very dense. The cavities of endoplasmic reticulum are distended. Well developed Golgi complex are usually found at the periphery of oocytes. Annulate lamellae consist of parallel flat sacs with a length of 1.5—2.0?m. There are structures like nuclear pores on the flat sac. Some bunchs of fibrous material in the cytoplasm of oocytes are called yolk plates Each yolk plate consists of a regular alternating dark and light bands with a periodicity of 20nm. Cortical granules are round with a diameter of 0.2—0.4?m. They are wrapped up in a membrane. Their electron density is high.

6 cases of gamete intra-fallopian transfer (GIFT) were performed in cooperation with the Department of Gynaecology and Obstetrics of The Third Teaching Hospital of our university in 1987. All the six women aged less than 41 years and have failed to be pregnant as long as ten years. One fallopian tube is patent at least. Two of them were pregnant after operation of GIFT. The rate of success was 33％. We used Ham's F10 medium mixed with different concentrations of fetal cord serum or mother's serum to prepare respectively follicular flushing medium (FM), sperm washing medium (SW), growth medium (GM) and transfer medium (TM). Clomiphene citrate and human menopausal gonadotropin (HMG) were used for inducing growth of follicle. HCG was given by intramuscular injection when two or more follicles were measured 16 mm in diameter by pelvic ultrasound. 32-34 hours later, follicular aspiration were performed by abdominal operation and the oocytecorona-cumulus complexes (OCCCs) were collected and trimmed under stereo microscope. The semen samples were obtained by means of masturbation 2-3 hours before operation. After centrifuged twice, the liquified semen was mixed with SW and incubated with 5％ CO_2 in air at 37℃ until GIFT.The OCCCs and 25?l processed semen were loaded into a special catheter and transferred into one fallopian tube. Then the transfer procedure was repeated for the other fallopian tube. The level of HCG in blood was examined from day 11 after transfer in order to diagnose pregnancy.