Disease (f the kidney.—In those organic diseases of the kidney which are characterized by anasarca and the passing of urine coagu lable by heat and acids, the albumen of the blood is more or less deficient in proportion; and this is marked by a corresponding dimi nution in the specific gravity of the serum. In a letter to Dr. Bright, published in the first volume of that author's Reports of Medical Cases, page 83, Dr. Bostock states, in re ference to the blood in these diseases, that the crassamentum was for the most part co vered with a thick buffy coat, and was gene rally of a firm consistence. The appearance of the serum was more varied. It was occa sionally turbid, and upon standing for twenty four hours a white creamy substance rose to the surface ; but no proper oily matter could be detected in it. On exposing it to heat, it coagulated in the ordinary manner, except that the coagulum seemed to contain an unusual number of cells, and that a greater quantity of serosity separated from it. " I think I may venture to say," adds the writer, " that the serum generally in these cases contained less albumen than in health, although I am not able to state precisely the amount of this dif ference. The serosity which drained from the coagulated albumen on being evaporated was found to consist in part of an animal matter possessing peculiar properties which seemed to approach to those of urea; it was partially soluble in alcohol, and was acted upon in a somewhat similar mariner by nitric acid." The above remarks were made on specimens of blood furnished from time to time by Dr. Bright. The number is not stated, nor was the specific gravity of the serum taken. Dr. Bos tock gives a case, however, (page 85,) where, after stating that the crassamentum was re markably buffed and cupped, he adds, " The serum was also worthy of attention, as taken in connexion with the state of the other fluids. Its specific gravity was almost exactly the same with that of the urine, being no more than P013, which I believe to be lower than had ever occurred to me in the numerous expe riments which I have made upon this sub stance. We have here, therefore, an example of blood exhibiting a very great deficiency of albumen, at the same time that we observe the mode in which it passes off from the system by means of the kidney, while this organ has its appropriate office of secreting urea nearly suspended. I regret that I did not attend particularly to the specific gravity of the other specimens of dropsical serum which you sent me. From sortie incidental remarks in my notes, I suspect that its specific gravity would have been found lower than ordinary ; but it is a circumstance which I shall be anxious to ascertain when any opportunity occurs." This suspicion is completely confirmed by other cases that have occurred to myself, in which the fact was also established beyond doubt, that the animal matter found by Dr. Bostock in the serosity was not merely an approach to urea, but that principle itself possessing all its usual characters. The following may serve as an example of light serum.
William Squires, aged 54, labouring under or ganic disease of the kidneys and chronic bron chites with anasarca, had for many months voided urine which coagulated on the appli cation of heat or the addition of nitric acid.
The specific gravity of his blood at 88 Fahr. was 1.041 Do. Serum at 68 1.021 healthy standard 1.030.
This blood contained in 1000 parts, 3.845 fibrine : healthy standard 2.1 to 3.56 55.000 albumen : healthy standard 65 to 69 In this case 100 grains of urine contained 6.666 albumen. There was consequently nearly one eighth as much albumen in the urine as in the blood, and the patient lost as much of that con stituent daily, as if he had been bled to the extent of four ounces.
The following cases are from notes with which I have been favoured by Dr. GAL Barlow,
who has devoted much attention to the exami nation of the blood and urine in this disease.
No. 1. A patient affected with general ana sarca—Urine copious, clear, pale, coagulable by heat and nitric acid : specific gravity 1.011. Blood cupped and buffed, serum milky : spe cific gravity No. 2. Man aged 48, anasarcous—Urine dingy brown, natural in quantity, acid, coagula ble ; specific gravity 1.017, contained 41 per cent. of albumen. Serum of the blood, specific gravity 1013.
No. 3. A man who was found on post-mor tem examination to have granulated kidneys. Urine reddish brown, very scanty, coagulable ; specific gravity 1.008. Blood cupped and buf fed ; specific gravity (of the whole blood) 1.037.
In my paper on the blood in the Medico Chirurgical Transactions, vol. xvi. I have stated the case of a woman forty-eight years of age, who for ten weeks had complained of pains in her loins, anasarcous swelling of her legs, and ge neral debility, and who passed urine which was in a high degree coagulable. I examined her blood, and found it to contain 0.43 per cent. of fibrine, and only 1.61 per cent. of albumen. The specific gravity of the serum was 1.020 at 600 Fahr. In that paper I have also observed that in several cases marked by coagulable urine, I have examined the specific gravity of serum with which Dr. Bright has fur nished me, and have always found it much below the healthy standard.
It is not, however, in this complaint ex elusively that the albumen of the blood will be found deficient in proportion. In other dropsical affections it will sometimes happen that a proportion of albumen more than equi valent to the fibrine effused will disappear from the circulation. Eleven days after tap ping a young woman, in whom ascites had supervened upon rheumatic affection of the heart, she was observed to be filling again very fast. A few ounces of blood were taken from the arm, and this blood was found to contain 0.319 per cent. of fibrine, and only 3.51 per cent. of albumen. Her serum had a specific gravity of 1-023.
The experiments of MM. Prevost and Dumas (Annales de Chimie, vol. xxiii.) which have since been repeated by Gmelin and Tiedemann (Poggendorff's Annalen), prove satisfactorily that urea exists in the blood after the kidneys. have been extirpated, and consequently that it is not formed, but merely abstracted by those organs. So long, however, as the kidneys act, we cannot expect to find it, since it is removed from the circulation as fast as it is formed, and never exists in any considerable quantity.
In these cases of diseased kidney a result analogous to that which follows extirpation occurs, for while that organ is permitting albu men to pass through it unchanged, the urea which it should separate is very generally if not always found in the blood. This I have proved in repeated instances, and it is now so generally admitted from the experiments of Prout, Chris tison, and others, that it is scarcely worth while to cite cases. Dr. Bright, vol. ii. p. 447, al ludes to several specimens of serum from patients under this disease, which he had sent me for examination, in some of which I did, and in others I could not detect urea. In one very remarkable instance of a young woman, the albuminous state of whose urine constantly existed for above three years, the urine con tained less than one-third of the normal pro portion of urea, while about one per cent. of albumen supplied the deficiency. The serum of the blood was, as I have already remarked to be usual in this disease, of very low specific gravity, being only 1•021. The quantity of al bumen in 1000 grains amounted, after careful drying, to only 50 grains instead of 78 (Le canu's healthy standard), and it contained fully as much urea as the urine itself, the 1000 grains yielding nearly 15 grains of that principle.