Observations on the Cast Preparation of the Blood Vessels of Endocrine Glands by Means of Injection of Polyester-Resin

Abstract

The author has investigated with the cast preparation methods which have hereto been widely adopted, and found that polyester-resin is the best injecting material. Polyester-resin, unlike acrylic-resin, does not require a colloidal solution, and makes polymerization injection possible at any desired time by simply adjusting the quantity of the promotor. And injections can be very much simplified. This resin, injected into an artery, can be transported with the natural flow of the blood into veins. In making cast specimens, it is necessary first to erode the tissue of the resin with caustic soda, and to immerge it in warm water of 50°-60°C for about an hour at the time of rinsing. The purpose of the immersion and rinsing is to remove the insoluble sediments caused by soap (which has been produced by fat of the specimen and caustic soda). As for the injection of the resin into the suprarenal gland and thymus, a satisfactory result can be obtained by injecting into the heart through the incision made in the common carotid artery immediately after draining the blood.The author has made several kinds of cast specimens of vascular system of endocrine glands by means of injection of polyester-resin and confirmed the following characteristic views, as the result of his observations these specimens : 1. The Thyroid GlandIn many cases the lobular arteries show a subtle tortuous action. The follicular arteries enter follicles and form a capillary network and go out of the opposite side as follicular veins. The size of the capillary network wrapping the follicle is related to the developing period of the follicle.2. ThymusThe trunk arteries and veins of thymus are second in number to those of suprarenals. The branches of the small arteries which run between the cortex and medulla of lobules flow toward the surface of the cortex, and some of them turn round and collect in the cortex-medulla veins while some flow into the veins which run around the lobular rand. The capillaries in the surface of the thymus and mark are observed to take sometimes the form of a glomerular structure. In the Mark there are blood vessels which may be considered as of an open nature or sinus vessels. In the glomerular structure of the medulla are found brocks of the resin.3. The Suprarenal GlandThe suprarenal arterial trunks are numerous and branch out into many arteries before entering the suprarenal capsule cortex. In the glomerular zone the blood is observed in a small circulating system. In the fascicular zone the blood vessels run in parallel to the medulla and hardly anastomose. There are two vein systems in medulla, one of which reaches the medulla as the perforated arteries and collect in the veins via the capillaries, while the other connects with the veins via the reticular zone of the cortex. Both, however, flow into the central veins. Sinus capillaries are observed in the medulla capillaries.4. OvariumIn all animals, typical types of spiral arteries may be observed, in the cortex although a slight difference exists depending on the animals. The blood vessel structure of the bovine follicle consists of double blood vessel walls. In the Corpus luteum glomerules of the capillaries are observed.5. The TesticlesThe testicular arteries show a marked spiral appearance prior to the entry into the testicles. In the case of a pig, the external arteries go inward and turn round near the mediastinum testis and branch out toward the surface. In the case of a rabbit, sinus capillaries are observed in the terminal part.6. The PlacentaTwo human umbilical arteries are united on the placenta while bovine umbilical arteries are united each other by large vessel to the placenta. The arteries and veins on the placenta are running mostly in parallel, but when they cross each other, the arteries run over the veins. In the case of the bovine placenta,