Full Idea
There are two opinions of essence: one suppose a certain number of those essences according to which natural things are made, and wherein they do exactly every one of them partake, and so become this or that species. The other more rational opinion....
Gist of Idea
The less rational view of essences is that they are moulds for kinds of natural thing
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 3.03.17)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.418
A Reaction
The more rational view is essence as the inner constitution which gives rise to the other properties. The view described here views essences (he says) as 'moulds', and has problems with unusual individual animals that are misfits.