ITS QUANTITATIVE ANALYSIS. 441 



the object of investigation (that is to say, the constituents should 

 be calculated for 100 parts of solid residue). So much has already 

 been said in reference to the necessity of this point in a rationa 

 investigation of the urine, as insisted upon in Becquerel's and 

 my own observations,* that it would be alike uninteresting and 

 superfluous to revert to the reasons which led us to establish this 

 rule, more especially as it must be obvious from all that has been, 

 and still remains to be, mentioned concerning the urine. It 

 may, however, seem as if we were too strenuously insisting upon 

 this very important point; for this rule by no means entirely 

 precludes the analysis of any other urine besides that which has 

 been collected in twenty-four hours. For, independently of the 

 fact that the analysis of the entire quantity of urine discharged 

 from the bladder at one time, is not only admissible, but even 

 highly desirable, when considered in a scientific point of view, we 

 may derive accurately scientific and purely physiological results 

 by adopting a method I have elsewhere recommended, of com- 

 paring together the different solid constituents in the urine, without 

 restricting the examination to the twenty-four hours 5 urine. The 

 comparison of the numbers representing the solid constituents 

 frequently gives very unexpected results, which cannot be obtained 

 from a mere comparison of the complete analysis of the twenty-four 

 hours' urine, or of any other urine. By way of illustration, we will 

 simply refer to our remarks at p. 95, in which we showed that we 

 had been enabled, by a comparison of the solid constituents of 

 hepatic venous blood with those of portal blood, to arrive at several 

 conclusions which could not have been obtained independently of 

 this mode of calculation, but which are very important, and throw 

 considerable light on the metamorphoses effected in the liver, the 

 physiological import of the hepatic function, and the rejuvenescence 

 of the blood. This is even more essential in respect to the inves- 

 tigation of the urine, since water in general plays a far less im- 

 portant part, or, at all events, does not stand in so definite a 

 relation to the solid constituents here as in other animal fluids, 

 a remark which applies equally to daily urine and to any individual 

 specimen. Indeed it would be wholly illogical to insist that ana- 

 lyses should be rigorously limited to the twenty-four hours' urine, 

 since such a method could not fail to lead to errors and misappre- 

 hensions. We need hardly remark, that in acute diseases the 

 character and composition of the urine may change very consider- 

 ably in the course of twenty-four hours; and this is not only the 

 Journ. f. pr. Ch. Del. 25, 3. 1-21, and Bd. 27, S. 257. 



