Scientia Sinica

128 SCIENTIA SINICA Vol, V

of disintegration. Another specimen taken 181 hours after the wound-making (Plate VII, fig. *), shows that the wound has healed to a certain extent, the new epidermis is extraordinarily thick, there is a thick layer of connective tissue under the spidermis, the number of leucocytes in it has decreased to the normal extent, and the cartilage has ceased to disintegrate. This speaks that 144 hours after the formation of new epidermis 1s completed, disintegration of the connective tissue is still going on under it, and simultaneously new connective tissue is formed. When the process reaches a certain extent, as shown in the case of 181 hours after the wound-making, the disintegrating substances not only continue to form connective tissue, but also begin to form new cartilage. The living substance first forms epidermal cells, then connective tissues. This process follows a definite sequence.

The auther in his study of the tissues of lymph node in 1937" found.one kind of small bodies in the connective tissue of the lymph node. These bodics can develop into undifferentiated cells, which, in turn, form various kinds of leucocytes. Under normal conditions there is a certain percentage of leucocytes developing from the small bodies.

The facts cited above show that there is a definite rule followed by the development of tissues. Of what mechanism is underlying this sequence and rule we are still ignorant. It should be investigated in future in the light of Pavlov’s theory. As proved by the experiment of Professor Zazipin, “in the organism, not only the cells but all the non-cellular living substance is con- trolled by the nervous system.” The sequence and rule of development of the disintegrating tissues and of the formation of cells in the organism is of vital importance; without this rule, a pathological state will arise.

The literature relating to the development of living substance into tissues of organism, and the facts the author has observed in his own experiments, such as the role of living substance in wound-healing, and the development of small bodies in the development of leucocytes, make him consider in a broader sense the formation of cells from the living substance in the organism. In the organism, the tissues under disintegration and destruction are not all going to die, while they may develop into new tissues and cells under favourable conditions.

SUMMARY

I. Different stages of growth of new epidermis were examined during wound-healing on the rabbit's ear.

Il. Disintegrating tissues, including fragments of leucocytes, macrophages, collagenous fibres, and cartilage, were discovered in front of and along the margin of the growing epidermis.