The concept of the energid (which refers to “energy,” or “vital force”; in modern terms, adenosine triphosphate, ATP) is that the smallest unity of life is the nucleus and the amount of protoplasm the nucleus can “control” metabolically. The concept of the cell as a nucleus-protoplasm “unit” confined by either a cell membrane or cell wall (e.g., mammalian or land plant cells) is rejected. Examples of multinucleate organisms such as coenocytic algae are presented as “proof of concept” of the energid. (...) [Abstract and keywords not in original.]. (shrink)