88. Now philosophers have troubled themselves exceedingly on the question of the origin of substantial forms. For to say that the compound of form and matter is produced and that the form is only _comproduced_ means nothing. The common opinion was that forms were derived from the potency of matter, this being called _Eduction_. That also meant in fact nothing, but it was explained in a sense by a comparison with shapes: for that of a statue is produced only by removal of the superfluous marble. This comparison might be valid if form consisted in a mere limitation, as in the case of shape. Some have thought that forms were sent from heaven, and even created expressly, when bodies were produced. Julius Scaliger hinted that it was possible that forms were rather derived from the active potency of the efficient cause (that is to say, either from that of God in the [171] case of Creation or from that of other forms in the case of generation), than from the passive potency of matter. And that, in the case of generation, meant a return to traduction. Daniel Sennert, a famous doctor and physicist at Wittenberg, cherished this opinion, particularly in relation to animate bodies which are multiplied through seed. A certain Julius Caesar della Galla, an Italian living in the Low Countries, and a doctor of Groningen named Johan Freitag wrote with much vehemence in opposition to Sennert. Johann Sperling, a professor at Wittenberg, made a defence of his master, and finally came into conflict with Johann Zeisold, a professor at Jena, who upheld the belief that the human soul is created.