Delousing on Shabbat (- Mishna, Shabbat 1:3)

Question

In the Mishna, Shabbat 1:3, it states (amongst other things) that one should not delouse one's garments by candlelight on Shabbat (ולא יפלה את כליו... לאור הנר). The following mishna, however, states that eighteen enactments were made on the day that representatives of the school of Shammai outnumbered the representatives of the school of Hillel, and the gemara interprets this particular ruling from Shabbat 1:3 as being amongst those eighteen.

Am I to understand, therefore, that the school of Hillel previously permitted delousing on Shabbat? It strikes me that such an activity would be a toldah of borer or gozez, or even hatzad tzvi. I presume that I must be misreading something, but am not sure what. Any advice would be appreciated.

Answer 1

Somebody just drew a beraita to my attention (Shabbat 107b), which I think might answer my question. In a discussion that concerns whether or not lice spontaneously generate, Rabbi Eliezer's opinion is brought to the effect that one who kills a louse on Shabbat is as liable as had he killed a camel. Rabbi Yehoshua disagrees, saying that one is permitted to kill a louse on Shabbat.

I know that the whole question of whether Rabbi Eliezer is of the school of Shammai or Hillel is a complicated one, though he does always seem to hold the views of the former. Rabbi Yehoshua, of course, is of the school of Hillel. Their disagreement here may shed light on the difference of opinion between the disciples of Hillel and Shammai in Shabbat 1:3 as well - though I note that some mefarshim (like the Rambam) hold contrary to the view that this was one of the eighteen things they enacted anyway.