IN DISEASES. 463 



these relations may occur in the most various forms of disease. 

 The once prevalent idea that albuminuria was a specific disease, 

 instead of being only a symptom of different diseases, is not 

 entirely exploded. 



But there likewise exist abnormal substances in the urine, 

 which differ so widely from the substances commonly contained 

 in that fluid, or in the animal organism generally as, for instance, 

 red, green, and blue pigments, cystine and xan thine that they would 

 appear to indicate the existence of some definite pathological pro- 

 cess or some specific form of disease. Such may indeed be the 

 case, but all who have observed the occurrence of these matters 

 must be aware that none of these rarely observed substances have 

 been found to appertain to any special form of disease. 



Amidst the confusion which prevailed in pathological chemistry 

 as to the composition of the urine in special diseases, the ingenious 

 idea suggested itself to certain inquirers of inventing entirely new dis- 

 eases in accordance with the constitution of the urine, and the nature 

 and quantity of the various substances which it contains, instead 

 of determining the composition of the urine with reference to the 

 disease. These diseases were named the uric and oxalic acid dia- 

 theses, the urea diathesis, &c. Observers thus fell into the same 

 errors of which the older physicians had been accused; namely, 

 that of classifying diseases in accordance with individual symptoms, 

 instead of grouping them in natural families based upon distinct 

 processes rather than symptoms. As we have already frequently 

 expressed our dissent from the assumption of any such diatheses, 

 it would be superfluous again to revert to the subject. But, in oppo- 

 sition to this, it might be asked, is not diabetes mellitus a diathesis ? 

 and is it not generally assumed to be a special disease ? According 

 to our view, this phenomenon is only a symptom,- standing in a 

 causal connection with a definite series of symptoms, in the same 

 manner as many other symptoms are also associated with their 

 respective phenomena. Thus, if in consequence of any anomaly 

 in the metamorphosis of animal matter, from a mechanical or phy- 

 siological obstruction, the conversion of the sugar in the blood 

 should be impeded, it will be very rapidly separated by the kidneys, 

 as Bernard, Kersting, and myself have proved by direct experi- 

 ments; this separation cannot, however, be effected, as we have 

 already seen in experiments on animals, without the abstraction of 

 a large quantity of water; the blood becomes poor in water, and 

 hence arise the thirst, the suppressed cutaneous transpiration, and 

 the parchment-like skin of diabetic patients. We almost invariably 



