A good deal of this perek deals with the laws of healing on Shabbat, a realm which is only indirectly related to wounding. It has already been explained in earlier chapters that the Sages prohibited medical treatment on Shabbat, except in life-threatening situations. It was determined that the reason for this prohibition is to prevent the preparation of medicinal substances on Shabbat. Such preparation involves the prohibited labors of grinding and crushing, as well as other Torah prohibitions. Due to this concern, various medical treatments, even many that do not involve the ingestion of medicine, were prohibited. Thus, this chapter specifies and defines various healing procedures. Some are prohibited because they are well-known cures. Others remain permitted because performance of these actions does not necessarily indicate that one is engaging in a healing practice, since perfectly healthy people also engage in these activities. The explanation of this rule, as well as an enumeration of the circumstances under which it applies, is the subject of this chapter.
As an example of common medical procedures in Talmudic time, the Gemara relates the following:
One who swallowed a snake should be fed hops in salt, and then he should be made to run a distance of three mil. The Gemara relates: Rav Shimi bar Ashi saw a person who swallowed a snake, and Rav Ashi appeared to that person as a horseman. Rav Shimi fed him hops with salt and made him run in front of him for three mil, and the snake came out of him in pieces. Some say that Rav Shimi bar Ashi was the one who swallowed a snake, and Elijah came and appeared to Rav Ashi as a horseman. He fed him hops with salt and made him run in front of him for three mil, and the snake came out of him in pieces.
Even though it is uncommon, it is not impossible to swallow a small snake. However, the Gemara is most probably referring to swallowing a tapeworm, known as the Taenia, which resembles a snake. The remedies mentioned in the Gemara are effective in killing a tapeworm.