http://www.rabbisedley.com/halacha/kashrut/Danger1.pdf
Talmud Nida 17a
Rabbi Shimon bar Yochai said: There are five things that if someone does them they forfeit their lives, and their blood is on their heads. One who eats peeled garlic, or peeled onion, or peeled egg, or drinks diluted drinks that have been out overnight; one who sleeps in the cemetery, one who cuts their
fingernails and throws them into the public domain, and one who lets blood and then has marital relations. One who eats peeled garlic: even though it was placed in a basket and sealed shut, nevertheless an evil spirit rests on them. But this only applies if there was no root or peel left on it, but if some of the root or the peel was left, it is not a problem.
Tzitz Eliezer 18; 46
I was asked regarding peeled onion and garlic that was left out overnight. [The questioner] wanted
to claim that if they are well covered and closed in the fridge that saves them so that they may be eaten, and they don’t need to be thrown out, since sometimes this leads to a great loss, and it also wasteful to
the food. This leniency doesn’t seem to work [based on the Talmud], however, it seems that
[nevertheless] there is room to be lenient in a case of loss, and to rely on the fact that this statement in the Talmud is not brought in either the Rambam or the Tur or Shulchan Aruch, and is only mentioned in a
few of the later sources. It could be that the Rambam and the authors of the Tur and Shulchan Aruch held in their greatness that this statement is not the Halacha, or that it does not apply nowadays because nature has changed, like we find in many other areas. Also, even if we are concerned in principle with this Halacha nowadays, like we find many of the great poskim were concerned, there are nevertheless many ways that it is permitted. We learn from the Sma”k two kinds of permission - either mix them with something else, like bread, or make sure to leave some of the peel with them (even if it has already been peeled off), and this prevents the evil spirit. Another permitted way is to put salt on them. Also, some people hold that the prohibition is only if they are raw and not cooked, and conversely, some hold only cooked and not raw. Therefore it turns out that if we want we can be lenient because of s’fek s’feka (double doubt). In other words, perhaps the law does not apply today at all, and even if it does, perhaps it is the other way (cooked or raw) from what we have. Even though this is a doubt in a dangerous thing (where we cannot be lenient), nevertheless, the doubt is not in a physical danger, but rather a spiritual, segula, concern. And we see that many people are not careful about this and nothing happens to them. Furthermore, in Shu”t Yad Meir he claims that there is a simple leniency, even if we say that the Halacha does apply nowadays, that washing them off [before eating] helps, and removes the evil spirit. Even though this is not mentioned in earlier sources, even so, it seems that it should work, since even without this, essentially the evil spirit is not common nowadays anyway.
------------------
I have three questions:
1) What happened to the evil spirit that it is no longer common nowadays?
2) Are there other halachos in which we are concerned about the evil spirit? Why are we more concerned there than here?
3) Is throwing the fingernails into the public domain in this gemara connected to the whole thing about pregnant women miscarrying?
