Aristotle explains induction from particulars in Posterior Analytics, Book 1, Chapter 31,
“It is owing to our inability to apply our senses, that certain questions remain unsolved. For could we but see what takes place, we should not still be seeking a solution. Not indeed that the mere act of sight would give us scientific knowledge ; but sight would be the means through which we should attain the universal. Thus if we saw the perforations in the glass, and the light-particles coming through, the cause of its illuminative power would be manifest. Sense would perceive the individual instance, and the intellect would recognize that this was a universal law.”
Aquinas explains induction from memory in his commentary on Posterior Analytics, Book 2, Lecture 20,
“But from remembrance many times repeated in regard to the same item but in diverse singulars arises induction, because induction seems to be nothing else than to take something from many things retained in the memory. However, induction requires some reasoning about the particulars, in that one is compared to another: and this is peculiar to reason. Thus, when one recalls that such a herb cured several men of fever, there is said to be induction that such a herb cures fevers. But reason does not stop at the induction gathered from particulars, but from many particulars in which it has been experienced, it takes one common item which is consolidated in the mind and considers it without considering any of the singulars. This common item reason takes as a principle of art and science. For example, as long as a doctor considered that this herb cured Socrates of fever, and Plato and many other individual men, it is induction; but when his considerations arise to the fact that such a species of herb heals a fever absolutely, this is taken as a rule of the art of medicine.
But someone could believe that sense alone or the mere remembrance of singulars is sufficient to cause intellectual knowledge of principles, as some of the ancients supposed, who did not discriminate between sense and intellect. Therefore, to exclude this the Philosopher adds that along with sense it is necessary to presuppose such a nature of mind as cannot only suffer this i.e., be susceptible of universal knowledge.”
Note: I replaced “experimentum” in the passage with the word induction.