Embryonic developments of chicken microvascular network can now be observed microscopically by Taharas method, suggesting that the exposure to pure oxygen caused no observable effects on microvascular system of hatched chicken. Mr. Yutaka TAHARA, a well-known Japanese high school teacherOihama high school,Central ward, Chiba prefecture, Japan has concentrated his teaching and research for the past 40 years, on the challenge of how to grow chick embryos to maturity in cultures and continuously observe their development, in eggs deprived of their shells. He selected this difficult task as the central plank in the biological training of his high school students. His life’s work was directed to encouraging these students recognize with their own eyes in real time, and record how the microvascular, respiratory and skeletal systems were established at the beginning of avian life. To achieve this, the efforts of his students were focused on the hatching of small domestic birds in the school class room. During this endeavour he established a novel technique for hatching domestic chickens and quail from eggs that had been denuded of their shells. The hatchability of the chicks in these cultures is greater than 30% for quails and 67% for domestic chickens [1], at present. Furthermore after hatching, these chicks have grown into normal adult birds which lived full, uneventful lives, laid eggs and raised chicks of their own at the homes of their “breeder students”. Tahara’s successful methods and interesting observations are summarized below. A particularly interesting feature of the technique is that it involved culturing the embryos in pure, moistened oxygen which the embryos tolerated unharmed. Tahara’s recent findings described below indicate that the main function of the eggshell is not to modulate the oxygen supply to embryos but to protect them from physical injuries caused by nesting and brooding movements of their parents and attack by predators, while avian embryos themselves are unaffected by hyperoxia.