3457. Families would be class-divisions, which correspond to the classes themselves.
3458. In no class therefore could there be more than four orders admitted, or five, if the sensorial organs be reckoned to constitute a special circle.
From the same reason there are no more than thirteen or seventeen families.—These names cannot meanwhile be so strictly adopted, because the classes are not of equal rank, as has been observed; on this account it is necessary to shove in here and there other divisions, which should be termed at one time Cohorts, at another, Alliances.
3459. If the animals of a class differ from each other, it is only possible by their bringing to bear in addition to their characteristic organ some other organ, and consequently becoming similar to an earlier or later class.
3460. Yet nevertheless in this ascent the animals could never outstep the confines of their own circle. There can be no Dermatozoon which could have bones; for in that case it would be an Osteozoon, and belong to another province.
Every class therefore comprises as many orders only as there are circles with which it comes into contact. Thus in the first circle there is only one order, in the second two, and so on.
Each class therefore includes also as many families only as the circles which are touched by it contain classes. Thus the first to the third class has three, the fourth to the sixth, six; the seventh to the ninth, nine; the tenth and so on, thirteen.
3461. The serial arrangement of animals into families is naturally difficult; but in Physio-philosophy we have to treat not about the execution of the Systematic in detail, but concerning its principles.
FIRST CIRCLE. INTESTINAL, OOZOA—MUCUS-ANIMALS.
First Class.