Complex sentence: He made important contributions to clinical education, based on his own medical practice, and in "De Fibra Motrice" advanced the theory that the solid parts of organs are more crucial to their good functioning than their fluids.
Split into simpler sentences: He made important contributions to clinical education, based on his own medical practice. His "De Fibra Motrice" advanced the "solidist" theory that the solid parts of organs are more crucial to their good functioning than their fluids.