PATHOLOGY AND ETIOLOGY.--The precise mode in which chyluria is brought about is unknown. It is to be inferred, in view of our existing knowledge, that there has been produced, in some way, in each instance a communication between the urinary and chyliferous systems, although exactly where such communication is has as yet only been guessed at. It may be in the kidney itself, or its pelvis, or the ureter, or in the bladder. Cases originating in the tropics have been found associated with elephantiasis, but this is not very frequent. Dilatation of cutaneous lymphatics, producing cutaneous papules and vesicles and a discharge of lymph from them, has also been noted coincident with chyluria. Prout,[4] among the earlier writers on this subject, and more recently Bence Jones,[5] Waters, Bouchardat, Robin, Bernard, and Egel, did not consider a positive lesion necessary, but ascribed the condition to a vice of nutrition and blood-making, accompanied by a slight consequent textural alteration in the blood-vessels of the kidney, through which the elements of the chyle transuded. Waters[6] says that "the main pathological feature of the complaint is a relaxed condition of the capillaries of the kidney," which permits the transudation. [Footnote 4: _Stomach and Renal Diseases_, 4th ed., London, 1843.] [Footnote 5: _Lectures on Pathology and Therapeutics_, 1868, p. 256.] [Footnote 6: _Med.-Chir. Trans._, vol. xiv. p. 221, 1862.] The results of examination of the blood, in cases of chylous urine, by Bence Jones, Rayer, and Crevaux, who found in certain instances an excess of fat, have been quoted in support of these views, but these examinations seem to have been microscopical and not chemical, and the results have not been confirmed by recent observers. Such views were also upheld on theoretical grounds by Bouchardat,[7] based on the greater commonness of the disease in warm climates. He reasoned that when the heat-producing elements, whether absorbed from food or produced by metamorphoses of other proximate principles, are in excess, and an elevated external temperature does not favor their consumption, their elimination is attempted by certain organs, notably the liver and kidneys. The effort by the kidneys seems, however, to be attended by a structural change in the blood-vessels, as the result of which blood is {117} eliminated with fat, especially at the beginning of the disease. Later the blood disappears, but the albumen remains some time longer, disappearing finally with the fat. [Footnote 7: _Ann. de Thérapeutique_, 1862.] Bernard and Robin also compared the blood of such cases to that of geese artificially fattened, being that condition of blood which is normal after digestion but transient. Egel also held similar views, ascribing the imperfect elaboration to the effect of hot climates.