[Seasonal structural and functional changes in the rabbit heart].

A study was made of some characteristics of the function and ultrastructure of intact rabbit heart during varying seasons. These characteristics appeared markedly different in winter, spring, summer and autumn. During the development in the myocardium of pathological processes (as a result of aorta coarctation and diphtheritic intoxication), the amplitude of changes in some parameters that characterize the function and ultrastructure of the heart was decreased. The author concludes that it is advisable to make control experiments during the appropriate season while carrying out physiological and morphological investigations.