We now begin the second chapter of the tractate, the chapter of 'Ein Ma'amidin', starting with Mishnah 1. The Mishnah lists a series of things that were forbidden or restricted because of the suspicion that pagan society was suspected of the gravest transgressions. In practical halachah, most of these laws do not apply nowadays, since societies do not tolerate such behavior, and a police force arrests those who engage in it. In the time of the Mishnah, however, that was not the case, and therefore idolaters were suspected of every terrible thing imaginable.
"Ein ma'amidin beheimah b'fundeka'os shel ovdei kochavim mipnei shechashudin al ha'revi'ah":
One may not leave an animal - cattle, for example - in an inn run by an idolater, because we suspect him of sinking to the depths of bestiality. One of the seven Noahide laws is the commandment concerning marital relations, which forbids relations with an animal. Its source is the verse "Therefore a man shall leave... and cling to his wife, and they shall become one flesh": since Adam and Chavah came from a common source, a man leaves his parents and joins with his wife - specifically in the relationship of a man and a woman - and through their union they become "one flesh", meaning a child who combines the two of them. From here we learn that this is the proper bond between a man and a woman, and not a union that has no capacity to produce offspring, for there we do not have a man and a woman but a human being and an animal, and therefore it is forbidden.
The concern, then, is that the Jew will transgress the Torah prohibition of "lifnei iver", placing a stumbling block before the corrupt innkeeper, and therefore he may not leave his animal under the innkeeper's control. This law applies even when the innkeeper has animals of his own, since it stands to reason that he would prefer to abuse an animal that does not belong to him and keep his own animals in good condition. For this same reason, even though according to the strict law it is permitted to sell small livestock to a non-Jew, we saw in the previous chapter that there were places that had the custom not to do so, out of this very concern.
"V'lo tisyached ishah imahen mipnei shechashudin al ha'arayos":
A Jewish woman may not be alone with non-Jewish men, since we suspect them of immorality and of harming her.
Seemingly, though, a woman is forbidden to be alone with Jewish men as well - so what is different about a non-Jewish man?
It is true that there are restrictions of yichud between unmarried Jewish men and women, but there are many scenarios in which they are permitted to be together. For example, when the man's wife is present, we are not concerned that he will act improperly with an unmarried woman. All this applies to a Jewish man and woman; with a non-Jewish couple, however, this is not so, for we are concerned that the pagan man will not care about his wife and will harm the Jewish woman, and therefore being alone together is forbidden even in such a scenario.
"V'lo yisyached adam imahen mipnei shechashudin al shefichus damim":
A Jewish man, too, may not be alone with a non-Jew, because of the concern that idolaters were suspected of murder, and he might kill him. With a Jewish woman, murder itself is not the primary concern, because we assume that women are not regarded with the same hostility and are able to arouse mercy and compassion in men, so killing them is considered unlikely. But a non-Jew killing a Jewish man is entirely within the realm of possibility, and therefore being alone together was forbidden.
These laws do not apply in practice nowadays, since we have a police force, and in any society in which Jewish blood is not considered ownerless - if an idolater kills a Jew, the police will arrest him and he will be sent to prison. The enforcement itself is what permits it. Therefore nowadays it is entirely permitted to remain in the office at night even if the only people present are the Jew and his non-Jewish colleague, and even if the latter is an actual idolater: the prohibition of yichud does not apply, since the police enforce the law and protect, and anyone who does something terrible faces consequences.
"Bas Yisrael lo t'yaled es ha'ovedes kochavim mipnei shemeyaledes ben la'avodah zarah":
A Jewish woman may not serve as a midwife and assist an idolatrous woman in giving birth, because in doing so she helps bring another member of the wicked pagan nation into the world. This prohibition applies when she does so for free; for payment it is permitted, mainly because if she were offered a fee and refused, it would generate enormous hostility and hatred between pagan society and Jewish society, which could lead to terrible consequences. On Shabbos, however, it is forbidden even for payment, since the woman can always excuse herself and say: "I do not work on Shabbos."
"Ovedes kochavim meyaledes bas Yisrael":
A Jewish woman giving birth may accept the help of a non-Jewish midwife. Nevertheless, we do not extend her complete trust, so the two of them may not be left entirely alone; but when there is supervision and other people are present in the hospital, it is permitted.
"Bas Yisrael lo taniq b'nah shel ovedes kochavim":
A wet nurse is a woman who nurses someone else's child. In the era before infant formula, someone had to nurse the baby, and if the mother could not or did not want to, another woman was brought in for the task. Now, a Jewish woman who works as a professional wet nurse may not do so for a non-Jewish woman. Even though payment is involved, she always has a way to excuse herself, since this is a far more invasive arrangement - being required to nurse a child on a regular basis; her husband might object to it, and so on. For all these reasons a Jewish woman can always avoid taking on the role of wet nurse for the baby of idolaters, and therefore she must do so.
There are two situations in which it is permitted:
Fear of hostility: When there is a concern that refusal will arouse great hostility and endanger the Jewish community, it is certainly permitted.
For her own benefit: A woman with an overabundance of milk who is in pain and needs to empty it out - nowadays there is a pump for this, but in the time of the Mishnah a baby was needed - and since she is doing it for her own benefit, she may nurse a non-Jew's baby.
"Ovedes kochavim menikah b'no shel Yisrael birshusah":
A non-Jewish wet nurse may nurse a Jewish child, provided that it is done in the domain of the Jewish woman - in her home and in the presence of the family. We do not send the child to the home of the non-Jewish nurse, since there the concern is that she might kill the baby. And even in the Jewish woman's home, at night, when the woman is there alone, there is a problem with it.
In light of all this the Shulchan Aruch writes that even where it is permitted it is certainly preferable to avoid it: the milk of a non-Jewish woman is kosher, just like the milk of a Jewish woman, but it dulls the heart and blocks it up to a degree. Spiritually it is not fitting that a person's source of nourishment should come from an idolatrous woman, and therefore it is much better to obtain a Jewish wet nurse.
In summary: The chapter of 'Ein Ma'amidin' opens with a series of restrictions stemming from the suspicion that idolaters are guilty of bestiality, immorality and bloodshed: one does not leave an animal in their inns because of 'lifnei iver', a woman may not be alone with them, and a person may not be alone with them. We examined the laws of midwifery and nursing - the prohibition against delivering and nursing the child of an idolatrous woman, and the leniencies of payment, fear of hostility and her own benefit, along with the permission to accept help from a non-Jewish woman in the Jewish woman's domain and under supervision - as well as the principle that the milk of a non-Jewish woman, though kosher, dulls the heart, and therefore a Jewish wet nurse is preferable.