STRUCTURE AND FUNCTIONS OF THE URETERS. 517 



As in birds and reptiles, which eliminate principally uric acid, ligation of the 

 ureters likewise induces a comatose state, it was necessary to think of other sub- 

 stances as possibly causing the toxic symptoms. Meissner observed prostration 

 and twitchings develop in dogs after injection of kreatinin. Cl. Bernard, Traube, 

 Ranke, Astaschewsky, Feltz and Ritter, and others attribute the phenomenon 

 to an accumulation of the neutral potassium-salts; Schottin and Oppler suggest 

 the accumulation of normal or abnormally decomposed extractives, Thudichum 

 that of the oxidation-stages of the urinary pigment. Possibly many substances 

 and their decomposition-products act in conjunction. R. Fleischer found a reduc- 

 tion in the elimination of sulphuric and phosphoric acids in advance of the ure- 

 mic attack in man. 



On placing various substances occurring in the urine kreatinin, kreatin, acid 

 potassium phosphate, uratic sediment from human urine directly upon the sur- 

 face of the cerebrum, Landois observed the development of all signs of uremia. 

 There occurred, particularly, fully developed convulsive seizures, with intervals 

 of rest, in dogs, with subsequent coma. Also, many other secondary phenomena 

 of uremic eclampsia could be thus induced. Urea is inactive in this direction, 

 ammonium carbonate, leucin, sodium carbonate, sodium chlorid, potassium 

 chlorid, feebly active. 



After long-continued excessive ingestion of food, together with the use of 

 spirit, and slight activity, there occurs, principally in conjunction with respiratory 

 disorders, derangement of metabolism, and not rarely a marked accumulation of 

 uric acid in the blood. The latter is deposited in the joints and their ligaments 

 and cartilages, principally of the foot and the hand, and gives rise to inflammatory 

 and painful attacks gouty nodules, uric arthritis. Rarely, the kidneys, the 

 heart, and the liver are involved. In the vicinity of the foci, the tissues undergo 

 necrosis. Food containing nuclein is to be avoided; also meat-broths, meat- 

 extract, sodium chlorid; while cheese, peptone, legumins, and aleuronat are to 

 be commended. As to the amins, piperazin, lysidin, v lycetol, urotropin, the in- 

 vestigations are not as yet concluded. As uric acid is more readily soluble in 

 solutions of urea, the administration of this substance has been advised. Uric 

 acid introduced into the blood or into the lymphatic system causes changes in 

 the renal epithelium, in the form of uric-acid spheroliths between and within 

 the cells of the convoluted tubules. Administration of adenin, while it does not 

 increase the excretion of uric acid, favors its deposition in the kidney amid in- 

 flammatory symptoms. In birds, long-continued administration of oxalates, 

 sugar, acetone, phenol, gives rise to deposition of urates in the urinary tubules, 

 as well as in the serous and the synovial membranes, and these have disappeared 

 after administration of piperazin. 



Human urine, when injected beneath the skin or into the veins of animals, 

 has a toxic and even fatal effect, particularly in the case of infectious diseases, 

 diseases of the liver, carcinoma, exophthalmic goiter, and, in accordance herewith, 

 after extirpation of the thyroid gland. The toxic properties are due to organic 

 (toxins) and inorganic constituents, principally potassium-salts. Pregnant ani- 

 mals are especially susceptible to this poison. 



STRUCTURE AND FUNCTIONS OF THE URETERS. 



The pelvis of the kidney and the ureter possess a mucous membrane con- 

 stituted of delicate connective-tissue fibers with many embedded cells, upon 

 which a laminated transitional epithelium is situated. The deepest layer of the 

 latter is provided with small, round, soft cells. Then follows a layer of more 

 nearly vertical, club-shaped and bulbous colls, whose attenuated extremities 

 ramify between the cells of the deepest layer; the free surface is covered by cubical 

 cells, which finally are surmounted by a homogeneous cuticular border. Beneath 

 the epithelium there is a layer of adenoid tissue, containing disseminated lymph- 

 follicles. In the pelvis of the kidney, the mucous membrane contains isolated 

 small grape-like mucous glands, which are present also in the ureter. The muscular 

 coat consists of an internal somewhat thicker longitudinal layer and an external 

 circular layer, to which, in its lower third, a number of disseminated bundles of 

 longitudinal fibers are added. All of these layers are rather freely interwoven 

 with connective tissue. The external connective-tissue sheath forms a sort of 

 adventitia, in which the larger vessels and the nerves, together with the ganglia, 

 are situated. The layers of the ureter may be followed upward to the pelvis of 

 the kidney and to the calices. They finally line the pelvis itself only with mucous 



