I might think (that he goes free) even if he knocked out a milk tooth, (which grows back); it is, therefore, written "eye." Just as an eye does not grow back, so the tooth (in question must be one which) does not grow back. This tells me only of tooth and eye. Whence do I derive (the same for) all of the other organs? It is derived inductively (binyan av) from the two, viz.: Tooth is not like eye, and eye is not like tooth. What is common to them is that they (i.e., their maimings) are permanent maimings of external organ prominences which do not grow back, (the maiming of which) causes the servant to go free, so (the maimings of) all such organ prominences which do not grow back cause him to go free.