Two discussions of eggs: one, from Michael of Ephesus, on the egg as a boundary between death and life; another, from Aetius of Amida, on the best way to cook eggs (soft boiled, soaked in wine and fish sauce and cooked on a double-boiler).
Lemma: “The reason for this is that nature produces the eggs, as it were, before [their] time, because of its own incompleteness…” (Aristotle, Generation of Animals 3.8, 758b19)
"In what follows, he (sc. Aristotle) discusses the reason why insects produce at first a grub which moves itself and is generally speaking an animal; then, once the grub has grown, it turns into an egg, lacking sensation and movement; then it turns into a different animal from the grub. He says that since an insect’s nature, because of its inherent weakness, is in itself unable to nourish and complete the embryo, what it produces is incomplete. And if in addition to generating an incomplete embryo, its nature generated something lacking soul and sensation as well, the embryo would cease to exist. But if this were the case, it is quite likely that the insect-kind would be absent from the world.* So it must be for this reason that nature generates an animal that is able to be nourished from itself, and it feeds on itself until it reaches completion.** Having reached completion, it dies.*** For living and eating are granted to it so that it becomes complete, but once it has reached completion, there is no longer any point for it to eat, and so no point for it to live.**** At this moment it dies, and it is then like an egg surrounded all around by a shell.***** Later, when what is inside of this shell has been completely concocted by the climate as if by a bird and has changed into an animal, it emerges."
758b19 «Τούτου δ’ αἴτιον ὅτι ἡ φύσις ὡσανεὶ πρὸ ὥρας ᾠοτοκεῖ διὰ τὴν ἀτέλειαν τὴν αὐτῆς.»
Τὴν αἰτίαν διὰ τούτων λέγει, τίνος ἕνεκα πρῶτον μὲν σκώληξ γεννᾶται κινούμενος καὶ ὅλως ζῷον ὑπάρχων, εἶτα αὐξηθεὶς ᾠὸν γίνεται ἀναίσθητον καὶ ἀκίνητον, εἶθ’ οὕτω πάλιν ζῷον ἕτερον παρὰ τὸν σκώληκα. λέγει οὖν ὅτι ἡ τῶν ἐντόμων φύσις ἀδυνατοῦσα θρέψαι ἐν αὑτῇ καὶ τελειῶσαι τὸ κύημα διὰ τὴν οἰκείαν ἀσθένειαν, ἀτελὲς αὐτὸ γεννᾷ· ὥστ’ εἴπερ πρὸς τῷ ἀτελὲς αὐτὸ γεννᾶν καὶ ἄψυχον ἐγέννα καὶ ἀναίσθητον, ἐφθείρετο ἄν· εἰ δὲ τοῦτο, τάχιον ἂν ἐκ τοῦ παντὸς ἐξέλιπε τὸ τῶν ἐντόμων γένος. διά τοι τοῦτο γεννᾷ ζῷον ἐξ ἑαυτοῦ δυνάμενον τρέφεσθαι, καὶ τρέφεται ἕως ἂν τελειωθῇ, τελειωθὲν δὲ θνήσκει· τὸ γὰρ ζῆν καὶ ἐσθίειν δέδοται αὐτῷ διὰ τὸ τέλειον γεγονέναι, ἐπειδὴ δὲ τετελείωται, οὐκέτι χρεία αὐτῷ τοῦ ἐσθίειν, ὥστε οὐδὲ τοῦ ζῆν. καὶ ἐπὶ τούτῳ θνήσκει, καὶ ἔστι τότε οἷον ᾠὸν κύκλῳ περιεχόμενον ὑπὸ τοῦ κελύφους· εἶθ’ οὕτως τὸ ἐντὸς ὑπάρχον τούτου τοῦ κελύφους ὑπὸ τῆς ὥρας ὥσπερ ὑπὸ ὄρνιθος συμπεφθὲν καὶ εἰς ζῷον μεταβαλὸν ἔξεισιν.
*A reductio: if nature generated embryos without soul, i.e., without life, there wouldn't be any insects in the world; but, there are insects; so, nature does not generate embryos without a soul.
**The idea is either (1) that the grub is able to feed itself, or (2) that it is able to be nourished from the whole of its own body, unlike an egg, in which one part is food (yolk) and one part becomes the animal (white). Cf. GA 2.1, 732a28-32 and Michael’s comments; 3.2, 752a27-28.
***Michael might be thinking of allegories of metempsychosis. I have yet to find whether the psuchê (butterfly) was used as a symbol of resurrection by late Byzantine Christians. Whether or not that's what he has in mind, the idea is not Aristotle’s—he nowhere says that grubs die when they become cocoons, nor does he say, as Michael takes him to, that cocoons are akinêton or without movement; rather, he says they are akinêtisanta or at rest. Elsewhere, Aristotle claims cocoons move when touched, e.g. HA 5.19, 551a19-20. Just how familiar Michael was with the HA is not clear; but Michael is nevertheless right that in the passage he is commenting on, Aristotle emphasizes the lack of motion of chrysalids throughout. And even if allegories of metempsychosis are in the background, Michael is most likely drawing the following inference: if something is alive, it has nutritive (and sensitive) soul; if something has nutritive (and sensitive) soul, then it can (move, sense), eat, and excrete residues; cocoons do none of these things; hence cocoons are not alive. The inference of course would be false: at most it would imply that cocoons are asleep. Michael, however, likely sees that there would be a deeper problem in saying cocoons are alive in this sense of 'sleeping': on the one hand, the soul of the grub and the soul of the completed animal cannot be identical, since the animals have different bodily organs, and souls and the organs they use are correlative; on the other hand, it seems implausible that the grub should have both souls simultaneously. But if it cannot have both souls simultaneously, and it must have a soul, then it must have the souls successively, and so must ‘die’ in some sense. Michael, then, thinks it is better to say that the soul the grub had has perished, while what it left behind is something alive potentially, but actually dead, namely an egg, which comes back to life when warmed by the season. Michael hints that this is what he has in mind by emphasizing that cocoons are like eggs, although he does not explicitly distinguish actual and potential kinds of living. It's telling that another commentator, Philoponus, denies caterpillars perish, and claims they merely change from one form to another (On Physics 8, CAG 16 180,19-20). This suggests people other than Michael were thinking through this problem.
****Michael’s interpretation likely relies on the familiar Arisotelian claim that nature does nothing in vain: it would be in vain for an animal whose purpose is to become an egg to continue to live.
*****A similar point is made by Plutarch, Quaest. Conv. 2.3 (Moralia 636C3-D7)
"Eggs of hens and of pheasants are better, while those of geese and ostriches [literally, 'sparrow-camels'] are worse. Best for the body's nourishment are the ones called 'trembling' [i.e., soft-boiled], while runny ones nourish less, but are passed more easily. They soothe the roughness in the throat caused by shouting or an acrid humour, when they are plastered on the affected places and remain there like a poultice; they also cure roughness because their whole substance is not stinging. For the same reason, they heal roughness in the stomach, bowels and bladder. An egg boiled in vinegar, when eaten, dries the discharges in the bowels. And if you mix things suitable for dysentery or a colic disposition with it and then broil it on coals and give it to eat, you will offer no small benefit to your patients. Suitable for these dispositions are the juice of unripe grapes, unripe mulberry plastered on, ashes of snails burnt whole, and grape seeds, myrtle berries and similar things. Boiled eggs are hard to digest, pass slowly and provide thick nourishment to the body. The ones baked in hot ashes pass even more slowly and produce even thicker humours than them. Fried eggs have the least nutrition in every respect. For when they are cooked they become greasy and produce a thick humor that is bad and full of residues. Better than boiled and baked ones are those called 'curdled': briefly soaked in oil, garum and wine, and boiled on a double-boiler to a medium consistency. Eggs thickened longer become like boiled or baked ones. The same thing should also be done in cases where eggs are poured on a frying pan, taking the frying pan off the fire when the eggs are still soft."
Ὠὰ ἀμείνω τά τε τῶν ἀλεκτορίδων ἐστὶ καὶ τῶν φασιανῶν, φαυλότερα δὲ τὰ τῶν χηνῶν καὶ στρουθοκαμήλων. κάλλιστα μὲν οὖν εἰς τροφὴν τοῦ σώματός ἐστι τὰ τρομητὰ καλούμενα, τὰ δὲ ῥοφητὰ ἧττον μὲν τρέφει, ῥᾷον δὲ ὑποχωρεῖ. τὰς δὲ ἐν τῷ φάρυγγι τραχύτητας διὰ κραυγὴν ἢ χυμοῦ δριμύτητα ἐκλεαίνει, περιπλαττόμενα τοῖς πεπονθόσι τόποις καὶ προσμένοντα ὥσπερ τι κατάπλασμα καὶ τῷ τῆς ὅλης οὐσίας ἀδήκτῳ ἐκθεραπεύοντα καὶ τὰς τραχύτητας. τῷ δὲ αὐτῷ λόγῳ καὶ τὰς κατὰ τὸν στόμαχον καὶ γαστέρα καὶ κύστιν ἰᾶται τραχύτητας· ἐν ὄξει δὲ ἑψηθὲν ὠὸν εἰ βρωθείη, ξηραίνει τὰ κατὰ γαστέρα ῥεύματα. καὶ εἰ μίξας δὲ αὐτῷ τι τῶν πρὸς δυσεντερίαν ἢ κοιλιακὴν διάθεσιν ἁρμοττόντων, εἶτα ἐπ' ἀνθράκων ταγηνίσας, δοίης φαγεῖν, οὐ σμικρὰ τοὺς κάμνοντας ὠφελήσεις. ἐπιτήδεια δέ ἐστιν εἰς ταῦτα ὀμφάκιον καὶ ῥοῦς ἐπιπαττόμενος καὶ τέφρα τῶν κοχλιῶν ὅλων καέντων γίγαρτά τε σταφυλῆς καὶ μύρτα καὶ τὰ παραπλήσια. τὰ δὲ ἑφθὰ ὠὰ δύσπεπτα καὶ βραδύπορα καὶ τροφὴν παχεῖαν ἀναδίδωσι τῷ σώματι. τούτων δὲ ἔτι μᾶλλον βραδυπορώτερά τε καὶ παχυχυμότερα τὰ κατὰ θερμὴν σποδιὰν ὀπτηθέντα. τὰ δὲ ταγηνισθέντα χειρίστην ἔχει τροφὴν εἰς ἅπαντα· καὶ γὰρ ἐν τῷ πέττεσθαι κνισσοῦται καὶ παχὺν χυμὸν γεννᾷ καὶ μοχθηρὸν καὶ περιττωματικόν. ἀμείνω δὲ τῶν ἑφθῶν τε καὶ ὀπτῶν ἐστι τὰ καλούμενα πηκτὰ μετ' ἐλαίου καὶ γάρου καὶ οἴνου βραχέος ἀναδευθέντα καὶ ἐπὶ διπλώματος ἑψηθέντα μέχρι μετρίας συστάσεως. τὰ γὰρ ἐπὶ πλέον παχυνθέντα παραπλήσια τοῖς ἑψηθεῖσι καὶ ὀπτηθεῖσι γίγνεται. τὸ αὐτὸ δὲ χρὴ ποιεῖν κἀπὶ τῶν ἐπιχεομένων ταῖς λοπάσιν ὠῶν, ἔτι ἐγχύλων ὄντων ἀπὸ τοῦ πυρὸς αἴροντας τὴν λοπάδα.
Aetius of Amida, Libri Medicinales, II 134, 201,19-202,14 Olivieri