Mitotic complex in the cardiac field of chick embryos

1. The mitotic peculiarity of the ventricle has been studied. 2. Diffused mitotic activity is noticed throughout the tissue matrix. No definite mitotic zone is seen. The total mitotic activity varies in the different regions as well as in different times of growth. 3. Except in 3 day heart, the rate of cell division is always more in the central area. 4. The ratio of dividing nuclei to resting nuclei in the peripheral region of 3 day heart is higher than that in the central region. 5. The most important item in the individuation of this organ is that the total percentage of dividing nuclei in the different stages, always present a slender figure. However, the cell increase is continuous. 6. The frequency is at its maximum. (11.03%) in 13 day heart, and the minimum (3.09%) in 21 day heart. The percentage of divisional figures in other stages fluctuates in between them. The cell increase in the heart continues even after hatching.