Experimental Myopathies and Muscular Dystrophy. A Study of the Formal Pathogenesis of Primary Myopathies as Exemplified in the Myopathy of 2,4-Dichlorophenoxyacetic Acid The histochemical types of muscle fibres are described and a report presented of the histological and histochemical altera- tions in skeletal muscles (tibialis anterior, gastrocnemius and soleus muscles) of rats given intraperitoneal injections of the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-0). The liver and myocardium of the experimental animals were also examined. In skeletal muscle, alterations occurring acutely...