Eachorganasitisdeveloped，serves，byitsactionsandreactionsonthe
rest，toinitiatenewcomplexities。Thefirstpulsationsofthefoetalheart
mustsimultaneouslyaidtheunfoldingofeverypart。Thegrowthofeachtissue，
bytakingfromthebloodspecialproportionsofelements，mustmodifythe
constitutionoftheblood;andsomustmodifythenutritionofalltheother