The morphometry of the intramembranous particles (IMP) of the dog sinus node cells was studied with freeze-cleaved specimens under H-500 electron microscope. The photographs of IMP of the P cells and transitional cells were analysed with imaging analytical system (IBAS Ⅰ+Ⅱ type). The results are as follows. The mean area of IMP: on PF and EF faces of P cells are 25.800nm~2 and 17.816nm~2. The mean values of IMP on PF and EF faces of the transitional cells are 46.041nm~2 and 88.633nm~2. The averages of the perimeter of IMP on the PF and EF faces of P cells are 20.735 nm and 18.078 nm, respectively. And those of the transitional cells are 28.780 nm and 43.901 nm. The diameters of circles of IMP of PF and EF faces of P cells are 5.220 nm and 4.402 nm. Those of PF and EF faces of the transitional cells are 7.010 nm and 10.476 nm. The mean values of form factor of IMP on PF and EF faces of P cells are 0.653 and 0.643, and those of transitional cells are 0.627 and 0.573. The mumbers of IMP are 1325/?m~2 and 345/?m~2 on PF and EF faces of P cells, and the mumbers of IMP of the transitional cells are 3225/?m~2 on PF face and 590/?m~2 on EF face.

The microvasculature of the rabbit right ventricle was studied by the method of vascular corrosion cast and scanning electron microscopy. In the endocardium could be seen thin and sparse capillary network i. e. subendothelial capillary network formed by the branches of the arterioles passing through myocardium. In the myocardium, arteriole and its branches distributed in certain area. Sphincters could be seen in the beginning of the arterioles. Capillaries of the papillary muscle in right ventricle were parallel to muscle bundle and were thinner and sparser than those of the papillary muscle in left ventricle. Venous system in right ventricle wall was similar in architecture to that in left ventricle, postcapillary venule joined its corresponding venule in a "turnip root" like pattern. No A-V anastomosis could be seen, yet thebesian vessels and myocardial sinusoids directly opened into ventrical chamber could be found.

Observation had been made on two male adults' hearts.Under electron microscopy,it is found that the A-V node consists of three types of cells,i.e.P cells,transitional cells and Purkinje cells.Because the specimen was cut from the central part of the A-V node, therefore the general myocardial cells were not observed.One of characteristics distingui- shed from the sino-atrial node is the presence of a few Purkinje cells in the A-V node.The number of P cells is far less than S-A node,and the transitional cells are predominant.In the interstitial tissues of the A-V node,the collagenous fibers are not so much as in S-A node but a numbers of capillarie,fibroblasts,mast cells and non-medul- lated nerve fibers can be seen.

The specimens were taken from two adults' hearts, thirty-four and twenty-eight years of age respectively. The A-V bundle was taken from the middle part of postero-inferior edge of the membranous part of the ventricular septum. The moderator band were cut from its superficial and deep part. The pseudochordae tendineae were collected from the left ventricle. All of the samples were fixed by 4％ glutaraldehyde. The chief results were as follows:There are many Purkinje cells in the A-V bundle, moderator band and pseudochordae tendineae. The shape of the Purkinje cells is broader and shorter than the ordinary myocardial cells. The myofibrils and myofiliments of the Purkinje cells are less than of those of the ordinary myocardial cells. The mitochondria of the Purkinje cells were often situated around the nucleus. In the A-V bundle, a few transitional cells and general myocardial cells may be observed. Therefore the His bundle may be consisted of Purkinje cells transitional cells and a few general myocardial cells. Our findings are not in accordance with that of Glomset et al. They observed that the A-V bundle only consisted of the general ventricle myocardial cells. The intercalated discs present between the Purkinje ceils in the A-V bundle were not typical. Besides the intercalated discs, we observed two sorts of the junction types in the A-V bundle: (1) An intercalated disc was observed between a branch of a transitional cell and the lateral surface of the other adjacent transitional cell. (2) Through the collagenous septum, there was a junction between a transverse branch of transitional cell and opposite transitional cell.

Hearts from eight adult dogs were perfused through both coronary arteries with methylmethacrylate. Small specimens cut out from the left ventricular wall were eroded in 50% HCL for 5-7 days. The replicas were studied under the SEM (S-450). The main results were outlined as follows: The subendocardial capillary plexus composed of varied shapes and orientation of meshes was present. The capillary network of the myocardial layers was consisted of many parallel capillaries and between them a variety of models of anastomoses, such as "H" "K" and "8" modes etc, were observed. In our findings, it was demonstrated that the arteriole and venule were distributed between the myocardial bundles and their direction was often perpendicular to the myocardial bundles. The postcapillary venules were poured into venule by the "ginger or turnip root" arrangement. The replicas of the Thebesian veins were proved in our specimens. The A-V shunting was not observed.

Three fresh kidneys removed from three adult bodies were perfused through the renal artery with 5％ and 10％ ABS (a copolymer of allylcyanide, butadiene and styrolene). Small specimens removed from the kidney were digested in 50％ HCI. Cast replicas of renal arteries and their branches were taken and examined with SEM (S-450 or S-520). The results were as follows.The capillary network of the area of the polar cushion cell were observed at the hilum of glomerulus in our casts. Their appearances are triangular, tetragonal or comma-like. In general, the shape of the meshes of the capillary network was round, oval, triangular or tetragonal. The diameters of the meshes were smaller than that of the vessels themselves. The microvessels of the area of the polar cushion cell, which mainly originated from the afferent arteriole, were continuous with the capillary of the glomerulus. The afferent arteriole was often traveled in the central part of the area of the polar cushion cell. The function of the microvessels of the area of the polar cushion cell was discussed in this article.

The fine structure of the biomembrane of the sinus node cells in the dog wasstudied with the replicas of freezecleaved specimens.The intramembranous particles.(IMP)in the PF and EF faces of the plasma mcmbrane of the sinus node cells,were present.The density of the IMP on the PF faces was more dense than those ofEF faces,In general,the shape of the IMP of the plasma membrane(PF and EFfaces)exhibited spherical or spheroidal.The IMP of PF faces may be divided into,three groups,i.e.the larger,medium and small size.Numerous endocytotic vesicles.found on the PF faces appeared as circular depressions and as small walled craterson EF faces.No regular array of the vesicles had been observed on both faces,TheIMP of the mitochondrial cristae were more dense than those of the depression.TheIMP of PF face of the nuclear membrane were observed.Their size and shapepresent a uniform appearance.There were many nuclear pores in the surface of thenuclear membrance.In the cytoplasm,longitudinal and transverse sections of the myofibrils werefound.On the transverse section,the myofilaments of A and I band werepresent.The intercalated disk was observed.The gap junctions present between thesinus node cells were proved by Masson-Pevet et al in the rabbits but were notfound in our specimens.

The vascular architecture of the adult man testis was examined by using thevascular casting method combined with scanning electron microscopy.The circuitousmain branches of testicular artery ran radially from testicular porta towards testicu-lar free border in tunica vasculosa.The test(?)cular surface veins were accompaniedby the main branches of testicular artery and they converged from testicular circum-ference circuitously towards testicular porta.There were centripetal artery andvein as well as centrifugal artery and vein in the septula testis.The intertubularblood vessels and the peritubular capillary plexus were contained in the testicularlobules.The latter was made up of two capillary layers.The outer layer was capil-lary network interwined in fine capillaries.The inner layer was coarse capillarycircles.The interstitial capillary plexus was situated in interstitial tissue between theseminiferous tubules and compose of capillaries arising from the origin of someperitubular capillaries.

In this study, image quantitative analysis was made to investigate the effect of scald on arginine vasopressin (AVP) positive cells in the supraoptic nucleus (SON) stained with immunohistochemical method. Results showed that there was a decrease in the volume of AVP positive substance in the cells of SON following scald, which was significant immediately after scald (P

The course of estahlishing coronary collateral circulation has been studied after ligating the anterior descending branch of the left coronary artery (L. A. D.) of the heart in 20 rabbits. Another 5 rabbits were studied as control group. The experimental results were as follows: (1) The rabbit electrocardiograms EGG were made before and after the ligation of the L. A. D. The EGG of control group was made only before killing. In these experiments, the pathological changes of No. 28 were observed immediately after ligating the L. A.D. It was found that the T wave was inverted in standard lead I, and that the volts of the QRS complex in lead Vc fell apparently. This phenomenon may be interpreted as myocardial ischemia in the anterior wall of the heart. After ligating the L. A. D. the S-T segment of No. 27 in AVL lead elevated and exceeded I mm, and the depressive Q wave in Vc lead was greater than the one-fourth of the R wave before killing. All of the phenomenen observed in the rabbit entirely confirmed the myocardial infarction and myocardial ischemia. In No. 25, the T wave was inverted in standard lead I, and the QRS complex in lead Vc was not only shallow in depth but also very little. The conditions accounted probably for myocardial ishcmia. During 4 to 21 days after ligating the L. A. D.,the pathological changes in the EGG occurred frequently.The rabbit ECG gradually became normal from 21 st day on. (2) The coronary arteries of the rabbit hearts were injected with X-ray contrast medium and were examined. The X-ray film thus obtained were compared with the specimen after they were cleared. At the same time, sections of the heart walls (the infarcted area and its surrounding areas) of fifteen rabbits were studied carefully under microscope. Our primary impression was that only a few newly formed vessels in the central part of the infarct till the fourth day after ligating the L. A. D. The vessels surrounding of the infarct show a slight winding and distension. During 10 to 28 days, the number of the newly formed vessels in the infarct increased gradually day by day. The vessels surroundings the infarct were also highly crooked and distended, especially in the anterior wall of the right ventricle. This is possibly the most active period in the establishment of coronary collateral circulation. During 28 to 49 days, the morphology of the vessels in the infarct area became similar to that of the corresponding area of the control group. (3) The significance of the coronary collateral circulation on the heart wall was discussed.