The elements carbon, oxygen, hydrogen, and nitrogen pass through a cycle of changes from simple inorganic substances to the complex compounds of the living cell. Upon the decomposition of these bodies the elements return to their original state. During this transition those properties of protoplasm which were mentioned at the beginning, in turn, follow their path. From germination to death this course appears like a crescent, the other half of the circle closed from view. Where chemistry begins and ends it is difficult to say.—Jour. Fr. Inst.
A lecture delivered before the Franklin Institute, January 24, 1887.
Studien uber das Protoplasm, 1881.
Vines, p. 1. Rostafinski: Mem. de la Soc. des Sc. Nat. de Cherbourg, 1875. Strasburger: Zeitschr., xii, 1878.
Botany: Prantl and Vines. London, 1886, p. 110.