The thing (80v & 82r)

[MarcoP]

Here is some speculation.
These are some possible explanations for an enema appearing next to the cross of Christ.

1) The visual representation of a medical charm. We know that charms included the sign of the cross together with properly medical elements.

2) Some kind of exorcism. The enema could be symbolic and illustrating some kind of purification.

3) A witch ritual. One of the meanings of naked women in medieval art was “witches”.

In my opinion, the most likely is option 1, because the naked women cannot be Christian priestesses and it's unlikely they are witches (I can't see anything clearly “Satanic”). In this case, the wolkenband could be hinting to the metaphorical nature of the naked women (they represent other entities than actual people). E.g. the healing power of the cross, the healing power of the enema.

I don't think we are dealing with a literally balneological subject, but I also think the similarity with balneological manuscripts is conspicuous and not accidental: the subject is not exactly the same, but might be something related. For instance (this has often been proposed) it might be some kind of illustration of physiological principles personified as “nymphs”; in this case, the “enema” might be an instance of a “pump” representing pressure in corporeal fluids (at the moment, I have no specific idea of the possible meaning of the Christian cross in this context).
My personal opinion it that also the difference of this section from XV Century manuscript illustrations of the constellations is conspicuous and not accidental.