C. L. HOAGLAND 



our present knowledge concerning the underlying mechanisms of 

 muscular activity, the resources of practically every field of science have 

 been tapped. For the most part, the quality of the observations made 

 in the study of muscle has been high, due in a measure to the excellent 

 tools available for its study, and in part to the keen minds of the inves- 

 tigators for whom muscle biochemistry and physiology have held a 

 major interest. 



Until recently, little interest was exhibited in the application of 

 information dealing with the chemical and physiological processes in 

 normal muscle to an elucidation of aberrant mechanisms at work in the 

 production of muscle disorders. As a consequence, these hetero- 

 geneous diseases continue to bear the confusing labels which were 

 given them by the classical pathologists. On occasions, serious efforts 

 have been made to apply the concepts and techniques of biochemistry 

 and physiology toward a solution of the problems presented by these 

 diseases, but the workers have been few, and significant results have 

 been scanty. Nevertheless, on the basis of what is known concerning 

 the normal physiology of muscle, we are perhaps in a better position 

 with respect to this organ than for any other to derive information of 

 an exact and fundamental character which would be helpful in form- 

 ing a common basis for clarifying the muscle syndromes. Moreover, 

 through a physiological consideration of the affections of muscle, a 

 unique opportunity is open to the biochemist by means of which he 

 may evaluate certain basic information with respect to its usefulness in 

 achieving the goal that he has set for himself, namely, that of defining 

 disease in terms of the nature of specific alterations in cellular 

 mechanisms. 



Voluntary muscle constitutes nearly 43% of the total weight 

 of the body and is affected by a variety of diseases in which the primary 

 process appears to be located in the muscle fibers, and by yet another 

 group of diseases in which marked secondary changes in muscle are 

 apparent, but in which the primary process is located in the central or 

 peripheral nervous system. Few syndromes are more confusing than 

 the primary muscular disorders. The confusion is due in part to lack 

 of agreement on the clinical and pathological findings in these affec- 

 tions, and in part to the fact that, although these diseases have been 

 recognized as clinical entities for over fifty years, the pathogenesis has 

 remained obscure. It is becoming increasingly apparent that no 



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