UNIFORMITIES AND COMPARISONS AMONG COMPONENTS 383 



Some physiologists would say that recovery is ''of course" 

 rapid for those components that are handled by organs of large 

 proportions such as organs of respiration. This view regards 

 anatomy not only as separate from physiology but antecedent to 

 it. Equally, the ample organ is caring for those components for 

 which rapid elimination or absorption often arises. Again, in one 

 organ such as kidney there is at one time rapid elimination of one 

 component and slow elimination of another. No one knows 

 whether ample provision for eliminating Ji invokes hypertrophic 

 function with respect to any J2. Or, leaving organs aside, there is 

 provision for the rapid production of glucose within a dog and not 

 of raffinose. Shall the organism be said to lack inventiveness 

 toward making the latter substance, or shall the actual provision 

 be regarded as sufficient and any greater provision as encumber- 

 ing? Questions of this sort lead to no decisive answers; only the 

 description of the rates found while the investigator asks the ques- 

 tions, corresponds to the facts known. 



A problem of the organism is how to regulate the most compo- 

 nents, each in the largest range of rates, with the least machinery. 

 Were a separate machine (organ) present for each, the burden of 

 rarely active tissues would be enormous. By multiplying the uses 

 of one structural unit, economy of body is greater. It was once 

 widely supposed that one "organ" served only one function, 

 though I presume one function might include its dealing with 

 many components. 



The kidneys are examples of organs that regularly excrete 

 scores of components, and each in an independent or nearly inde- 

 pendent clearance. How the independence of one component from 

 another is secured, no one has ascertained. To some small extent 

 histological differentiation is correlated with diversity of the com- 

 ponents handled, e.g., glucose is absorbed in proximal tubules of 

 frog, chloride in distal tubules. But there are not so many visible 

 differentiations as components. In fact, unforeseen (foreign) 

 components {e.g., diodrast or phenol red in dog) are handled just 

 as specifically as usual ones. Recovery from excesses of a hundred 

 components occurs through one and the same kidney. 



"In a living organ we are dealing with something of which the 

 functions, if we speak of functions, are endless, since the activ- 

 ities are endless, constantly seeming to grow in number as we in- 

 vestigate further. Its true function, to the eye of a physiologist, 



