In the distribution of the Animals themselves, the Subjects and the products of this energy, into the principal Classes, we do not suppose chasms & intervacua or empty Interspaces between the Classes, but ascend from a lower to a higher by an interliminary — and the same principle holds good in the Dynamics of Organic Nature, and the Enumeration and the Order of the three Constitutive Forms of the Vital Energy.
Source: wiktionary