The development of the endocardial cushion and the ventricular septum of chicken heart was studied with SEM, TEM, light microscopy and histochemical methods. The results are as follows:1. The development of endocardial cushion begins from the proliferation of the endothelial cells which form cushion cells when these cells enter the cardiac jelly. Cushion cells also proceed mitosis and migrate toward the myocardium, and the endothelial cells cease proliferation when the reserve layers of cushion cells were formed. The fused endocardial cushion participates in the formation of atrioventricular orifice, the right tubercle prolongs toward the ventricular septum and eventually fuses with it.2. The cardiac jelly of endocardial cushion contains a great deal of hyaluronic acid which arranges in "trails", pioneering cushion cells migrate along the "trails" and change the component and arrangement of the matrix.3. Muscular ventricular septum is formed by aggregation of trabeculae inside the interventricular sulcus. The dorsal part of the ventricular septum fuses with the lower part of right tubercle of endocardial cushion and the ventral part fuses with the conus septum.

The morphogenesis of the heart and the formation of the epicardium were studied with SEM, TEM and light microscopy. The results are as follows:1. There are two stages in the development of chicken heart: First is the formation of cardiac loop. In certain places, the sulcus appears outside, and the cresta appears inside during this stage. The formation of the cardiac loop indicates the establishment of the anlagen of the heart; Second is the differentiation of the anlagen, including the septation of the heart and the shift of each part of the heart. The shift of the atrium and the conus results from the shift of the right and left ventriculum. 2. The epicardium is not differcntiatcd from the myocardium, but formed from the mesenchymal cells which proliferate in front of the sinus venosus. These cells migrate and cover the entire surface of the myocardium.

Fortyfour male Kunming mice, weighing 20-25g. were used. The HpD was injected (10mg/kg) into the caudal vein of 32 mice individually. After 48 hours, the kidneys were radiated directly by the dye-laser for 10 minutes (630nm, 250-300J/cm~2). Then, the kidneys were observed at different times. 12 normal male mice served as control. The experiment demonstrated that when HpD was activated by laser, it could produce the necrotic effect on the renal tissues. The different structures of the kidney showed different susceptibility to HpD-laser. The proximal convoluted tubules and capillaries were injured earlier than the distal convoluted tubules and the collecting tubules. The first morphologic changes observed electron microscopically were the swelling of mitochondria and the formation of vesicles on the cell membrane. Finally, they were completely disrupted. The damages of lysosomes, endoplasmic reticula, ribosomes and cell nucleus followed. The activity of some enzymes in the kidney were inhibited. The sequence of the extents of the enzymes being inhibited was AkP, AcP, Cytox, SDH. The mucopolysaccharides ran off the brush border in proximal convoluted tubules. The results of this study suggested that the various susceptibilities to HpD-laser are chiefly due to the different structures and their functional conditions in the kidney. The main photodynamic effect is presented as the injury of the membrane system of the cell.

During 14-17th days, the duodenum of the rat fetus was composed of stratified epithelium and peripheral mesenchyme. On 18th day, the mesenchyme began to protrude toward the basal aspect of the epithelium, resulted in the formation of primary villi. At the sametime, goblet cells and the primordia of intestinal glands appeared. The number of goblet cells,which located at the surface of the villi, increased gradually with the fetus age, whereas after birth the goblet cells decreased with the development and maturation of intestinal glands. From 19th day till 3-4 weeks after birth, the shape of villi changed continuously, and attained to the adult shape in 4th week.