600 OP SECRETION AND EXCRETION. 



tion of the kidney. The symptoms of Uraemia (as this condition has been 

 appropriately termed) are altogether such as indicate the action of a specific 

 poison upon the Nervous system; affecting either the Brain or the Spinal Cord 

 separately, or both together. In the first form, a state of stupor comes on rather 

 suddenly, out of which the patient is with difficulty aroused ; and this gradually 

 deepens into complete coma, with fixed pupils and stertorous breathing, just as 

 in ordinary kinds of narcotic poisoning. In the second form, convulsions of an 

 epileptic character, frequently affecting the whole muscular system, suddenly 

 occur; but there is no loss of consciousness. In the third form, coma and con- 

 vulsions are combined. It has been generally supposed that these results are 

 attributable to the accumulation of urea in the blood ; but clinical observation 

 affords sufficient evidence, that there is no constant relation between the severity 

 of these symptoms and the amount of urea in the circulating system; 1 and expe- 

 riment has determined that the other constituents of the urine do not exert any 

 more potent influence. 3 It seems probable, then, that some substance formed 

 at the expense of the normal constituents of urine, rather than either of these 

 substances themselves, is the real poisonous agent in cases of Uraemia ; and very 

 cogent evidence has been adduced by Prof. Frerichs, in proof of his idea that 

 the symptoms of this disorder arise from the conversion of the Urea in the cir- 

 culating current into Carbonate of Ammonia, by the agency of a suitable ferment ; 

 so that, however great may be the accumulation, it does not give rise to any 

 serious consequences, unless this ferment be also present. Two series of experi- 

 ments are described by him as supporting this doctrine; the first showing that 

 in cases of uraemic intoxication, a resolution of urea into carbonate of ammonia 

 is actually taking place, ammonia being found in the expired air when the first 

 symptoms make their appearance, and in the blood and in the contents of the 

 stomach after death; and the second proving that the injection of carbonate of 

 ammonia into the circulating current induces a train of symptoms essentially 

 corresponding with those of uraemia, stupor and convulsions occurring either 

 separately or conjointly. 3 It seems not improbable that, as in the case of the 

 retention of Bile in the Blood ( 631), many of the minor as well as of the 

 severer forms of sympathetic disturbance, connected with disordered secretion 

 from the kidney, are due to this directly poisonous operation of the decomposing 

 constituents of the urine, upon the several organs whose function is disturbed ; 

 and that many complaints, in which no such agency has been until recently 

 suspected especially Convulsive affections arising from a disordered action of 

 the nervous centres are thus due to the insufficient elimination of Urea from 

 the Blood. 4 



638. In order to form a correct opinion of the state of the Urinary secretion 

 in morbid conditions of the system, it is desirable to be acquainted with every 

 leading particular regarding its normal character. Fresh healthy Urine is a 

 perfectly transparent, amber-yellow-colored liquid, exhaling a peculiar but not 

 disagreeable odor, and having a bitterish saline taste. In all natural conditions 

 of the Human system (even when a vegetable diet is used), the urine possesses 



1 It has been remarked by Bright, Christison, G. 0. Rees, and Frerichs, that urea may 

 often be obtained in considerable quantity from the blood of patients suflFering under 

 "Bright's disease," who were at the same time free from all nervous symptoms. 



2 Thus Frerichs (as Bichat, Courten, and Gaspard had before done) repeatedly injected 

 from 20 to 40 grammes of filtered human urine, sometimes even with the addition of urea, 

 into the veins of animals, without any ill effects resulting. 



3 On this subject, the chapter on " Uraemia" in the admirable treatise of Frerichs "Die 

 Bright' sche Nierenkrankheit und dcren Behandlung," should be especially consulted. 



4 Of the truth of this view, which was propounded by the Author in the first edition of 

 this work, many illustrations have been since afforded ; among the most interesting of 

 which, is the very frequent coincidence of " Bright's disease" with Puerperal Convulsions, 

 first pointed out by Dr. Lever. 



