Propositiones de lithiasi tōn nephrōn

we establish.

VII.
The matter, however, from which stones are made, by the consensus of all, is a certain thick and earthy substance existing in some humor, as Galen in the cited places and Paulus, book 3, chapter 45, agree.

VIII.
Which humor most people establish as phlegm, since such matter is found in it, although Hippocrates, in the book On Popular Diseases, book 6, and Aetius, book 11, chapter 4, write that stones can also congeal from both bile and pus if retained for a long time in the kidneys.

IX.
That a similar earthy matter is found in the serum, although it may appear thin, both the demonstration itself—that it can be separated by boiling and turn into stone—and its saltiness declare: just as icicles, tufa, coral, and halcyonia nests or stones formed from sea foam sufficiently show that an earthy substance exists not only in sea water, but also in the most limpid water.

X.
We do not hesitate to assert that this matter provides the stone in the serum, although it may seem new to some.

XI.
Galen is inconsistent in assigning the efficient cause. For in one place he thinks the burning heat of the kidneys is required, as in On the Faculties of Nourishment, book 3, chapter 17 (which Alexander, Paulus, and Aetius also affirm), elsewhere, as in the last of the Aphorisms, book 3, he judges that a milder and more remiss heat can suffice. Whichever we posit (for we believe that stones can be generated from both, although the former compacts the matter more quickly, the latter more slowly), that heat will be either innate or adventitious.

XII.
Innate, as in the case of one who is hotter from birth or from the principles of generation.