4 ANALYSIS OF DISTURBANCES OF METABOLISM 



problem of life. Yet even here the ingenuity of our scientists has found a way 

 to probe more deeply into the cause of things, and, though still_ in the first 

 stages, the most recent investigations upon organs kept alive outside the body 

 (saturated with, blood, autolysis) have been followed by important results 

 which permit us to expect more surprising conclusions in the future. 



On the other hand, it must be emphasized that although our knowledge 

 of the chemical processes of metabolism is still comparatively primitive, the 

 laws of metabolism have been decidedly advanced by a more physical consid- 

 eration of the processes. The dynamic conception of the transition of food 

 products, thought out by Eubner, furnished a basis for labors in the clinical 

 pathology of metabolism upon which a superstructure might be raised with 

 ease and certainty, and upon this the imposing structure of modern laws of 

 metabolism in the diseased body was soon erected. 



If we take this as our actual theme, we note that in the clinical study of 

 metabolism in the last few decades quantitative investigations take precedence. 



The history of this begins with the publication of E. BischofE's book, 

 "Urea as the Measure of Metabolism" (1853). The method of estimating 

 the amount of urea by titration, first employed by J. v. Liebig, enabled BischoS 

 and Voit to undertake numerous investigations by which they determined the 

 laws of nutrition in the carnivora.^ 



Chossat had previously, by careful experiments with starving pigeons, 

 demonstrated the daily loss of weight and the amount of the excretions; and 

 Bidder and Schmidt in their book, " The Digestive Fluids and Metabolism " 

 (1852), described minutely the valuable results of their investigations regard- 

 ing the metabolism of carnivora (cat) under the most varied conditions of 

 nutrition. They were the first to relate in detail, after an investigation in 

 which all requirements were fulfilled, how to find in the urine and the feces 

 the nitrogen ingested in food in the form of meat, and upon this they founded 

 the law of nitrogen equilibrium. 



With the aid of the elementary analysis of urine and feces, and the care- 

 ful estimation of the factors of respiratory metabolism which were made pos- 

 sible by the help of v. Pettenkofer, the study of the quantitative analysis of 

 metabolism in Volt's physiologic laboratory in Munich soon attained great 

 technical exactness. With this came the facilities for studying the alterations 

 of decomposition under most varying circumstances, and particularly with 

 food of different nature and quantity, and thus it became possible to deter- 

 mine the laws of the total animal economy. 



CONSUMPTION OF FOOD IN THE HEALTHY 



A. THE LAWS OF NUTRITION 



The estimation of the amount of food required by the healthy human organ- 

 ism to maintain its equilibrium has been the subject of many experiments by 

 Voit and his pupils. 



1 Bischoff u. Voit, " Die Gesetze der Ernilhrung des Fleischfressers," 1880. 



