“They say that Christ passed through (διδεσαντα) Mary like water flows through a tube (καθάπερ ὕδωρ διὰ σωλῆνος ὁδεύει)”

[Secret Alias]

Irenaeus, Adversus haereses, 1.7.2

I find this position fascinating because (as I note in a previous thread) it squares with the radical monarchian view of the heretic described in Tertullian's Against Praxean. The idea here seems to be that not only were there two powers - Jesus and Christ corresponding to 'Son' and 'Father' - but remarkably that Jesus was not adopted as Christ (Son as Father) at baptism - as we might expect.

This heresy is often repeated in Patristic sources. For instance, Cyril ofJerusalem, Cat. illum., 4.9: 'The incarnation did not occur in semblance or fantasy, but in truth; neither did the Lord pass through the Virgin as if through a tube (ὥσπερ διὰ σωλῆνος διελθὼν)' (PG 33.465B), Chrysostom, in Mt. 4.3: “The Gospel says just enough to refute those who say that Christ passed through the Virgin as if through a tube (ώσπερ δια τίνος σωληνος παρηλθεν)”

But the reference to 'tube' has sexual connotations and it is worth noting that this exact phraseology appears in Porphyry's Ad Gaurum as part of an Platonic explanation for how the soul becomes ensouled in the body of the child:

Once I heard someone earnestly maintain to us21 that the male’s eager desire during the process of impregnation and the sympathetic [response] of the womb22 seize soul from the surrounding air through the breathing that is going on, transforming23 the nature that was the seed’s orchestrator24 with the help of a characteristic power to draw in soul.25 And [this soul] leaps out with the seed through the male as if through a pipe [διὰ σωλῆνος] and is again seized by the eager desire in the womb whenever it is suitably disposed to retain [the seed and soul]. And this is why the two have intercoursebecause it is through both that the soul is bound and confined, and the experience was called ‘conception’ because these happenings are like trapping a bird.26 But I laughed at these stories even then, and I know that I thought they merited remembering not because this fiction warrants any discussion but because this approach permits and reveals thousands of variations whenever someone refuses to place the soul’s entrance after its birth from the mother and traces back this occurrence to the embryos that are still in the belly and to the obscure situation concerning that condition. (4) For those who think that Plato said this sort of thing, determining the moment of the soul’s entry is problematic, and there will be at least an equal struggle for them when they try to show that the soul comes in from the outside rather than having a part of soul from the father be sown along with the seed (just as [a part] of nature [from the father is sown along with the seed]),27 if indeed the soul comes in simultaneously28 at the time of the sowing.

21. The theory described here falls into the first category in which the soul is said to enter into the semen.
22. The womb’s sympathetic response is also a desire, cf. prothumia at AG 2.3.6. That the womb is at it were a living thing that has a desire (epithumia) to procreate is a Platonic view (Tim. 91B-C). Cf. Plotinus 4.4.28.13-14.
23. metakinêsanta. Grammatically the subject is either masculine singular or neuter plural. Even though Porphyry just said that the male and the womb are working together to get the soul, the participle is probably referring only to the male here. He is the one who seizes the soul and with it transforms the semen’s nature into soul. In other words, on this theory the offspring’s soul enters into the father’s body and then exits with the semen. The womb’s own eager desire comes into the explanation later. It accounts for why this soul is retained by the womb (2.3.6). See notes 22 and 27.
24. cf. 10.3.7 [= 46,30 K].
25. The genetive tês psukhês appears to be objective rather than subjective. Cf. Iamblichus de An. §32.2-7, which describes this same position using the same terms (prothumia, helktikê idiotês, anapnoê, etc.). As Finamore and Dillon note in their commentary ad loc., this ‘has affinities to the doctrine of the Orphics’ (165). The Orphics seem to have advanced a doctrine of soul according to which there was a single universal soul that was somehow subjected to division into individual souls through individuals breathing in the universe’s air (cf. Iamblichus de An. §8 and §25 with Finamore and Dillon ad loc.). Cf. SVF 2.782-4 and Galen’s dunamis helktikê of the uterus with respect to the semen (de Usu Part. 2.323,9-10 Helmreich).
26. The Greek word sullêpsis can mean both conception and seizure (or trapping). Soranus (Gyn. 1.43) and Galen (de Sem. 66,7-11 De Lacy) give similar though less metaphysically loaded explanations of sullêpsis, where it is not the soul that is seized, but the semen. Cf. Michael Psellus Opuscula psychologica, theologica, daemonologica 23 (98,16-20 O’Meara), translated in Appendix 2.
27. Porphyry’s own view is that the semen does contain a portion of the father’s nature and carries this with it into the womb. See Introduction § 2.

I think therefore the source of this doctrine was a Platonist who understood God the Father to have literally given his seed to Mary in the womb passing on Christ directly into her womb. I am not sure that Irenaeus's explanation is accurate about the rest of the implications. We must also remember what is said about the Carpocratians that Jesus had a 'different soul' than the rest of humanity. This might well be a very old doctrine.

[Secret Alias]

It is worth noting that the discussion where this reference to the 'tube' appears in Porphyry immediately after raising the question whether or not the soul enters the womb with the sperm or after. Indeed the implication of this anonymous cited opinion in Ad Garum seems to have very significant implications for the heresy cited by Irenaeus. For the last time I quoted Porphyry I left out the most important part:

Once I heard someone earnestly maintain to us21 that the male’s eager desire during the process of impregnation and the sympathetic [response] of the womb22 seize soul from the surrounding air through the breathing that is going on, transforming23 the nature that was the seed’s orchestrator24 with the help of a characteristic power to draw in soul.25 And [this soul] leaps out with the seed through the male as if through a pipe [διὰ σωλῆνος] and is again seized by the eager desire in the womb whenever it is suitably disposed to retain [the seed and soul]. And this is why the two have intercoursebecause it is through both that the soul is bound and confined, and the experience was called ‘conception’ because these happenings are like trapping a bird.26 But I laughed at these stories even then, and I know that I thought they merited remembering not because this fiction warrants any discussion but because this approach permits and reveals thousands of variations whenever someone refuses to place the soul’s entrance after its birth from the mother and traces back this occurrence to the embryos that are still in the belly and to the obscure situation concerning that condition. (4) For those who think that Plato said this sort of thing, determining the moment of the soul’s entry is problematic, and there will be at least an equal struggle for them when they try to show that the soul comes in from the outside rather than having a part of soul from the father be sown along with the seed (just as [a part] of nature [from the father is sown along with the seed]),27 if indeed the soul comes in simultaneously28 at the time of the sowing. For just as the similarities of its body reveal that it has inherited from its parents something from the body, so too must the similarities in soul indicate the source from which it has been received.29 (5) And so our main concern shall be to demonstrate that the fetus30 is neither actually an animal nor potentially one in the sense of having already received soul, and from this it follows that the soul enters after birth. And even if we were to concede that the embryo itself is potentially or even actually an animal, we will still maintain that its ensoulment can be neither from the father nor from the mother, but only from the outside, so that this account of the soul’s entrance would not contradict Plato in this way, either.

So as you can see Irenaeus has cited the opinion correctly but failed to note that it is based on a Platonic understanding of how 'ensoulment' takes place during natural conception. In other words, in humans a particular embryo may take physical characteristics from either parent but - according to this 'expert' - the soul of the baby comes from the father with the sperm. All that the heretic known to Irenaeus has done is transfer this assumption about natural procreation to 'what must have happened' when the Father's seed (= Christ) came into Mary's womb viz. Jesus took the soul (or perhaps spirit) of the Father.

The important thing to see is that in Irenaeus and every subsequent expert those who promote this 'medical analogy' of the tube do so to reinforce that Jesus's soul had nothing to do with his mother. John of Damascus for instance denies the heretical believe that he came to "us through a pipe"
[ώς δια σωληνος], but has assumed of her [έξ αυτής], a human nature consubstantial to ours (De Fide Orth., Ill, 12). 'Assumed of her' denies that his soul was exclusively divine or Christ-like.

Indeed it would seem that the claim about 'passing through a tube' would not have been deemed to have been a special occurance but occurs in every conception. In other words, the heretic treated Mary's conception of Jesus as an otherwise typical conception where - when conception happens - the 'science' cited by the author claimed that the soul passed from the father to the child.