Just to tighten up on the context, let me quote the larger passage in its entirety:
Cicero dicit Hippocratem, nobilissimum medicum, scriptum reliquisse quosdam fratres, cum simul aegrotare coepissent et eorum morbus eodem tempore ingravesceret, eodem levaretur, geminos suspicatum; quos Posidonius Stoicus, multum astrologiae deditus, eadem constitutione astrorum natos eademque conceptos solebat asserere. Ita quod medicus pertinere credebat ad simillimam temperiem valetudinis, hoc philosophus astrologus ad vim constitutionemque siderum quae fuerat quo tempore concepti natique sunt. In hac causa multo est acceptabilior et de proximo credibilior coniectura medicinalis, quoniam parentes ut erant corpore adfecti, dum concumberent, ita primordia conceptorum adfici potuerunt ut consecutis ex materno corpore prioribus incrementis paris valetudinis nascerentur; deinde in una domo eisdem alimentis nutriti, ubi aerem et loci positionem et vim aquarum plurimum valere ad corpus vel bene vel male accipiendum medicina testatur, eisdem etiam exercitationibus adsuefacti tam similia corpora gererent ut etiam ad aegrotandum uno tempore eisdemque causis similiter moverentur.
So a little more specifically, Augustine is addressing the Hippocratic case of two boys who got sick and then recovered precisely at the same times. (The yet broader context is that astrology or fate is not the explanation of the breadth and longevity of the Roman empire; astrology doesn't even deal convincingly with the "problem of twins".)
I agree that consecutis ... prioribus incrementis
is an abl. absol. phrase. consequor
can be passive (sense 8 in OLD), which is how I take it here.
The medical explanation for the boys' simultaneous aegritudo
is that, first, since the father and mother were in a given state of health ["given state of health" sounds neutral, but adfectus
is frequently used of the condition of being sick, and that's the context here] at the moment of conception, thus the two fetuses immediately following conception (primordia conceptorum
) could thus be both affected [same connotation for adfecti
] such that, the earliest stages of growth having been reached in (?) the mother's body, they came into the world in an identical state of health; then, <they grew up in the same home under identical conditions ...>.
I'm hesitating a little on the prepositional phrase ex materno corpore
. The phrase is wrapped by the abl. absol. and would therefore seem to modify it, but ex
doesn't seem like the right preposition for what's happening in
the mother's body. But ex materno corpore nascerentur
makes perfect sense. Maybe it's a little of both (they were conceived by the father and the mother but nourished and delivered by the mother)?
Nesrad, I'm curious what you find "obscure" either in this passage or in A's style or logic generally. I often have to think through his train of thought to the point of getting a headache, but I don't think I think of him as "obscure".