Abstract
Each of the kidney, the lung, the liver and the mixture of the skin and the muscle of a four-month-old human embryo were separately minced, trypsinized and cultured in test tubes.
In the cultures of the kidney and of the liver, both the epithelioid and fibroblastic cells proliferated. In the cultures of the lung and of the skin-muscle, only fibroblastic cells proliferated. Upon successive culture passages, cells of the kidney and the lung ceased the multiplication almost completely at the third passage and the cells of the skin-muscle did so at the fourth passage. The fibroblastic cells of the kidney which proliferated vigorously in the primary culture, decreased markedly at the second culture passage.
The skin and muscle of a seven-month-old human embryo was treated and cultured by the same method as that of four-month-old embryo. Similarly fibroblastic cells proliferated, but the cell multiplication was much weaker than in those of the four-month-old embryo and ceased to multiply almost completely at the second culture passage.
