The contents of the _De Animalibus ad Caesarem_ may be inferred from the Prologue which is as follows: ‘In Nomine Domini Nostri Jesu Christi Omnipotentis Misericordis et Pii, translatio tractatus primi libri quem composuit Aristoteles in cognitione naturalium animalium, agrestium et marinorum, et in illo est conjunctionis animalium modus et modus generationis illorum cum coitu, cum partitione membrorum interiorum et apparentium, et cum meditatione comparationum eorum, et actionum eorum, et juvamentorum et nocumentorum eorum, et qualiter venantur, et in quibus locis sunt, et quomodo moventur de loco ad locum propter dispositionem presentis aetatis, aestatis et hiemis, et unde est vita cuiuslibet eorum, scilicet modorum avium, et luporum, et piscium maris et qui ambulant in eo.’ It seems tolerably certain that the substance of this prologue came from the Arabic original, which must have commenced with the ascription of praise to God so commonly employed by Mohammedans: ‘Bi-smilláhi-r-rahhmáni-r-rahheém’ (In the Name of God, the Compassionate; the Merciful).[83] The clumsiness of the Latin, which here, as in the body of the work, seems to labour heavily in the track of a foreign text,[84] adds force to this assumption. The hand of Scot is seen, however, where the name of our Saviour has been substituted for that of Allah, and also in the closing words, which ring with a strong reminiscence of the eighth Psalm. The churchman betrays himself here as in not a few other places which might be quoted from his different writings. By far the most interesting matter, however, which offers itself for our consideration here, lies in the comparison we are now to make between this book and a former work of Scot, the _De Physionomia_. This comparison, which has never before been attempted, will throw light on both these texts, but has a special value as it affords the means of dating, at least approximately, the composition of Scot’s version of the _De Animalibus ad Caesarem_.