Preface 



What a strange field is transport! Here the investigator gathers 

 information from kidney tubules, tumor cells, frog skins, gut sacs, 

 and toad bladders. With such as these he observes behavior that 

 violates the intuition of the enzymologist, morphologist, and 

 chemist, and observes the behavior of molecules that may have 

 proved inert in his every other test. 



Biological transport is by no means a new subject, but it is one 

 that has gained tremendously in interest from the various biological 

 sciences in the last few years. The subject evolved from two rather 

 discrete interests— that of permeability phenomena, extending back 

 more than 60 years, and that of problems of secretion. The difficulties 

 posed by the latter were found in the late 1930s to be associated with 

 the former. With the closer approach to the interpretation of other 

 cellular phenomena, the need to understand how substances and 

 reactions are segregated and brought together in the cell and in the 

 organism has become so pressing that many ingenious, indirect ap- 

 proaches to these questions have been discovered. Meanwhile, the 

 search for the means to identify directly the structures producing 

 transport has continued. 



This presentation grew from a short series of lectures to an 

 advanced biochemistry class, attended also by graduate students 

 of pharmacology, physiology, microbiology, genetics, and other 

 sciences. It should be interpreted more as a bibliographed syllabus 

 for that instruction than as a review. Accordingly, the author has 



