Rambam - 3 Chapters a Day

This chapter—like its source, Keilim, ch. 24—focuses on sets of three, describing several keilim of which there are three types: a) one that people lie or sit upon and which is therefore susceptible to midras impurity; b) one that is used to perform tasks; if someone would sit upon it, he would be told: “Stand up and let us perform our tasks;” such an entity is susceptible to the impurity connected with a human corpse and other types of impurity, but not to midras impurity, and c) something that is not susceptible to impurity, because it is not considered as a k’li at all or for another reason.
See also Halachah 16 where the general principles involved are delineated.

Because a person sits on it. See Chapter 26, Halachah 6.

And other types of impurity aside from midras impurity. See Chapter 25, Halachah 15.

One containing more than 40 se’ah. See Chapter 3, Halachot 1-2.

Because it will be turned upside down so that a person can sit upon it. See Chapter 26, Halachah 7. The Ra’avad emphasizes that the owner must think of using it for that purpose, as stated in that source.

But not to midras impurity.

Surrounded by borders on three sides [the gloss of Rav Ovadiah of Bartenura (Keilim 24:2)].

It is used to transport articles. If a person would sit upon it, he would be told: “Stand up and let us perform our task” (ibid.).

Since it is used to transport large stones, it may have holes large enough for pomegranates to fall through in it. Holes of this size would prevent the wagon from contracting impurity (Chapter 6, Halachah 1).

Its sides are turned inward, protecting a person on all three sides. As such, it is fit to sit upon [the Rambam’s Commentary to the Mishnah (Keilim 24:1); Kessef Mishneh].

Our translation is based on the Rambam’s Commentary to the Mishnah (op. cit. and 23:2).

For it is not used to lie or sit upon [the gloss of Rav Ovadiah of Bartenura (op. cit.:1)].

Because it is too small to serve any purpose other than sport or playacting [the Rambam’s Commentary to the Mishnah (op. cit.)].

Our translation is based on the Rambam’s Commentary to the Mishnah (op. cit.:5).

Because it is also used to sit upon (ibid.).

If a person would sit upon it, he would be told: “Stand up and let us perform our tasks” (Kessef Mishneh).

It is considered an entity that serves entities that serve man; see Chapter 24, Halachah 1.

Because it is also used to sit upon or to rest one’s feet upon.

It is considered as part of the table (the Jerusalem Talmud, Shabbat 17:2). The Kessef Mishneh states that it is impure, because food is served on it, like on the table itself.

This is speaking about an oversized closet which is therefore not susceptible to ritual impurity.

The Kessef Mishneh questions why this “bed” is susceptible to ritual impurity. Seemingly, like the leather wrappers on which olives are spread above (or like the bed used by weavers in this halachah), it does not benefit man directly. A possible resolution is found in the gloss of Tifferet Yisrael to Keilim 24:8. These “beds” have a border that causes them to be considered as receptacles.

In this instance, the “beds” do not have a border and hence are considered like flat wooden implements (ibid.).

The bracketed additions are based on the Rambam’s Commentary to the Mishnah (Keilim 24:9).

Because it is fit to sit upon (the glosses of Tifferet Yisrael and Rav Ovadiah of Bartenura to Keilim, op. cit.).

Because it is considered as a container and is unfit to sit upon (Tifferet Yisrael, op. cit.).

For merchandise, household goods, and the like.

And thus unfit to sit upon and hence, not susceptible to midras impurity [the Rambam’s Commentary to the Mishnah (op. cit.)].

See Chapter 23, Halachah 1, and the lengthy explanation in the Rambam’s Commentary to the Mishnah (op. cit.:10).

These are used as containers, but not to sit upon (Tifferet Yisrael to that mishnah). The Kessel Mishneh questions the Rambam’s ruling. He understands that these mats are used merely to place clothes upon. He, therefore, questions how they are different from the mats used for grapes mentioned in the following clause or the leather wrappers mentioned above.

For the beams in the vat and the like [the Rambam’s Commentary to the Mishnah (op. cit.].

Because they are not used as containers.

As stated in Chapter 4, Halachah 11, and Hilchot Metamei Mishkav UMoshav 7:8, since these are large containers, they are also used as seats. When they are initially made, there is an implicit intent to also use them for such a purpose.

For they are receptacles.

For all keilim made from the skin of fish- or for that matter, anything else growing in the sea—are pure. See Chapter 1, Halachah 3, and notes.

To place on the floor and sit upon [the Rambam’s Commentary to the Mishnah (op. cit.:12)].

See Chapter 24, Halachah 1.

To wrap clothes, knives, or needles [the Rambam’s Commentary to the Mishnah (op. cit.)].

I.e., a piece of leather from which these are cut [the Rambam's Commentary to the Mishnah (Keilim 24:8)].

I.e., it is still unfinished. See Chapter 7, Halachah 1.

Beitzah 14b relates that it is susceptible to impurity, because, from time to time, an attendant will wrap himself in a curtain to warm himself. Thus it is considered as a garment. See also Hilchot Kilayim 10:14.

I.e., for an apprentice learning to weave tapestries to copy [the Rambam’s Commentary to the Mishnah (op. cit.:13)].

I.e., rectangular pieces of fabric (Tifferet Yisrael, op. cit.:14).

Used to wipe one’s hands during a meal (ibid.).

Because one sits on it from time to time (ibid.).

See Chapter 22, Halachah 6.

The Levites in the Temple would wrap their harps in clothes. Most others would use leather containers (Tifferet Yisrael, op. cit.:14).

The Kessef Mishneh questions why a trapper might desire to rest against the glove. In his gloss to the Mishnah (op. cit.:15), Tifferet Yisrael explains that since these gloves are wide, at times, the trapper sits on them.

Thus it serves as a receptacle.

These are used to harvest soft fruits and protect one’s hands from getting soiled. As such, they are not considered to be serving man per se. See similar concepts above, Chapter 7, Halachah2.

Netlike head coverings worn by women through which their hair could be seen [the Rambam’s Commentary to the Mishnah (op. cit.:l6)].

Because the girl will take it off and sit upon it (ibid.).

Because it is a garment and will not be used to sit upon because its holes are larger (ibid.)

The holes of these hairnets are very wide. Since they are immodest, they are not considered as garments (Tifferet Yisrael, op. cit.:16).

Because they are supports for the feet.

Shoes of armor placed over an animal’s feet in war.

Shabbat 59a gives three reasons why these shoes are considered as receptacles and hence, susceptible to impurity: a) when no drinking utensils are available, soldiers use these shoes as cups, b) at times, they are worn by humans to protect their feet from brambles, thorns, and the like, and c) they are used as receptacles for oil.

This also refers to shoes made for animals (see Chapter 2, Halachah 7). If shoes were made for humans, even from such substances, they would be susceptible to impurity (Kessef Mishneh).

Thus when fashioning the k’li, it is considered as if the craftsman also had this intent in mind.

See Chapter 23, Halachah 1, and the sources mentioned there.

See Chapter 24, Halachah 11, et al.

Even though the liquids are merely derivatives of impurity (see Hilchot Sha’ar Avot HaTum’ah 7:1).

See Chapter 6, Halachah 2.

The Ra’avad objects to this ruling, following a different understanding of Keilim 24:17. The Kessel Mishneh explains the Rambam’s perspective.

The Rambam is citing the wording of the mishnah (Keilim 24:7). In his Commentary to the Mishnah, he states that the term “tablets” is being used loosely and refers to any two flat pieces of wood placed side by side, whether they are used as writing tablets or for other purposes.

This refers to a folding chair over which a scroll is placed to fuse it into a single entity (ibid.; see also ibid. 16:1). This conception is based on the simple meaning of the Rambam’s words here and Rav Kapach’s understanding of the Rambam’s Commentary to the Mishnah. The standard published text of that source and the Kessef Mishneh follow a different understanding.

The wax was used to seal letters closed [the Rambam’s Commentary to the Mishnah (Keilim 17:17)].

For it is a k’li with a receptacle.

A simple, flat board.

Because they are small.

See Chapter 13, Halachah 4, and Hilchot Sha’ar Avot HaTum’ah 7:3.
If the outer surface of the k’li contracts impurity from a primary source of Scriptural impurity, the inner side also contracts impurity (Pesachim 17b, quoted by the Kessef Mishneh).

With regard to sacrificial foods, by contrast, it does contract impurity (Kessef Mishneh, based on Keilim 25:9).

I.e., an indent in the rim enabling the container to be held without inserting one's finger inside of it. See the Rambam's Commentary to the Mishnah (Keilim 25:7).

The above applies even if the handle has a receptacle.

Our translation of this and the following terms is based on the Rambam’s Commentary to the Mishnah (ibid.:1).

The projections to which the handles are connected (ibid.).

The Ra’avad emphasizes that one should not use the k’li until it was dried. The Kessef Mishneh states that this concept is implicit in the Rambam’s words.

The Ra’avad objects to the Rambam’s ruling, but does not clarify his objection. The Kessef Mishneh offers two possible interpretations of the Ra’avad’s statement: a) that according to the Ra’avad, the opposite is also true. If the inner portion of such a receptacle contracts impurity, the outer portion does not, or b) if impure liquids touch the outer portion of such a receptacle, even the outer portion does not contract impurity. Since the impurity imparted by impure liquids is Rabbinic in origin, our Sages wanted to make a clear distinction in its regard.

I.e., keilim that do not have a receptacle.

This refers to utensils made from wood, bone, or glass.

I.e., a frame around the tabletop. See Keilim 25:1 and commentaries.

See Chapter 1, Halachah 10.

A roasting tool with a ladle to remove soup at one end and a three-pronged fork to remove meat at the other [the Rambam’s Commentary to the Mishnah (Keilim 13:2; 25:3)].

This ruling reflects the opinion of Rabbi Yehudah (Keilim 25:3). The Ra’avad differs, stating that Rabbi Meir differs in that source and, he maintains, Rabbi Meir’s opinion is supported by the majority of Sages. The Kessef Mishneh, however, supports the Rambam’s view.

Although the plow is not a container, there is a distinction between the contraction of impurity by its functional parts (parallel to the inner space of the receptacle) and it supporting beams (parallel to the external surface of the receptacle) [the Rambam’s Commentary to the Mishnah (Keilim 25:2)].

Both the Hebrew terms melamed and marde’a are translated as plow. With regard to a melamed, see Chapter 11, Halachah 23, where the Rambam states that a plow is comprised of: “A long, thick beam with something like a sharp peg implanted in its end from above. This metal [peg] is called a darban. On the other end below is a metal [projection] like a spear. The wood that is inserted into it and this iron piece is called a lance (charchur).”Keilim 25:2 speaks only of a marde’a and uses a similar description.

These seven handbreadths — and similarly, the four handbreadths mentioned in the following clause — were considered as necessary for the functioning of the plow. See also Chapter 20, Halachah 12.

I.e., they are considered as separate entities.

And thus neither is considered in the inner space of the other. See also Chapter 13, Halachah 12, where a more stringent ruling is given to a somewhat parallel situation.

As in the law that applies regarding a receptacle: If the inner space contracts impurity, the outer surface is also impure.

As is the law when impurity touches the outer surface of a receptacle.

I.e., in a case of impurity of Scriptural and not merely Rabbinic origin, the leniency mentioned in this halachah is not applied. Our translation follows the version of the Mishneh Torah suggested by the Kessef Mishneh, Ma’aseh Rokeiach, Mishneh LiMelech, and others. The standard printed text of the Mishneh Torah — and, in this instance, also the authoritative manuscripts cited in the Shabsie Frankel printing — follow a different version.

A Talmudic measure equal to 86 cc according to Shiurei Torah and 150 cc according to Chazon Ish. Diagram

A k'li must be immersed in a mikveh all at once. Even though the two measures are considered as separate keilim with regard to the contraction of impurity, they are considered as a single entity with regard to immersion.

As stated in Halachah 1.

With this specification, the Rambam excludes food which cannot be purified through immersion.

See Chapter 4, Halachah 1.

I.e., immersion in a container is not acceptable even if the container is large enough to hold the required amount of water.
Sefer HaMitzvot (positive commandment 109) and Sefer HaChinuch (mitzvah 175) include immersion as one of 613 mitzvot of the Torah. Sefer HaMitzvot, op. cit., clarifies that the intent is not that an impure person has an obligation to purify himself. {The commentaries explain that the Rambam agrees with the opinion that there is no mitzvah for a woman to purify herself after her nidah impurity). Instead, the mitzvah is that a man or woman who is impure can regain purity only through immersion in a mikveh.
See also Hilchot Metamei Mishkav UMoshav which states that after a zav, a zavah, a nidah, and a woman after childbirth contract impurity, they remain impure even if they remained several years without an impure emission, if they did not immerse in a mikveh. And Hilchot Issurei Bi’ah 11:16 states:
A woman does not ascend from her state of ritual impurity... until she immerses herself in a mikveh that is halachically acceptable while there are no substances intervening between her flesh and the water.... If, by contrast, she washes in a bath — even if all the water in the world passes over her — her state is the same after washing as before washing.... For there is no way of ascending from a state of ritual impurity to one of purity except through immersing in the waters of a mikveh, a spring, or a sea which is like a spring, as will be explained in Hilchot Mikveot.

Leviticus 14:9, 15:13; Numbers 19:7-8, et al.

Leviticus, op. cit., Numbers 19:8, 10, et al.

As the Rambam proceeds to explain, the intent of the verse is that the person must immerse his entire body, including his hands. As stated in Halachah 10, the prooftext also implies an exclusion: Just as the hands are visible, so too, it is only the visible parts of the body that must come in contact with water. Parts of the body that are not openly visible need not come in contact with the water.

I.e., that is where these principles are elaborated upon at length.

I.e., immerse in a mikveh.

I.e., even after immersion, the person’s impurity does not depart until nightfall.

The Rambam uses the expression binyan av, which is one of the Thirteen Principles of Biblical Exegesis. Literally, the term means “a building of a father.” The intent is that the Torah states a law regarding a particular subject. That subject then serves as a prototype and the same law is applied to all similar subjects. Similarly, in the case at hand, the prooftext states that a person or a k’li that contracted impurity through contact with the carcass of a crawling animal can regain purity through immersion. From that one instance, we learn that all impure people and objects can regain impurity through immersion unless the Torah explicitly states that other means of purification are necessary.
(The commentaries note that in Hilchot Issurei Bi’ah 4:3 the Rambam mentions a different verse to serve as a binyan av for this concept. It is possible to explain that there he is speaking about the purification of people, while here, the intent is both people and keilim.)

See Hilchot Keilim, chs. 18-19, with regard to the purification of keilim through breaking them.

The earth and anything attached to it are not susceptible to ritual impurity. Nevertheless, since the k’li was impure before it was attached to the earth, it remains impure after it was attached.

This refers to an earthenware container that has already contracted impurity. If it has not yet contracted impurity, there is room for leniency (see Merkevet HaMishneh).

Since the raw material from which glass keilim are made is sand (a type of earth), our Sages considered glass keilim like earthenware (Shabbat 15b).

As stated in Hilchot Keilim 23:1:
A mafatz is a mat made by interweaving cords, reeds, grasses, or the like. A mafatz is not one of the keilim mentioned by the Torah. Nevertheless, it is susceptible to the impurity associated with the support of a zav (midras impurity) according to Scriptural Law. [The rationale is that Leviticus 15:4] states “All surfaces on which one lies,” expanding the category [of articles susceptible to impurity. A mat is thus included, because] it is fit to lie on and is indeed made for that [purpose]. Similarly, it contracts impurity from contact with a human corpse and other sources of impurity according to Rabbinic Law, like all other flat wooden keilim, as we explained. This is a great general principle: Any entity that is susceptible to the impurity associated with the support of a zav is susceptible to other types of impurity.

The Ra’avad elaborates, explaining a slightly different perspective than the Rambam.
According to the Ra’avad, simple wooden keilim can be purified through immersion. It is only mats that cannot be purified, because they are not made of wood and are not considered as keilim at all. [See the gloss of the Merkevet HaMishneh who explains that the difference of opinion between the Ra’avad and the Rambam corresponds to that between Rashi and Tosafot (Shabbat 84a).]

By being tom, it is considered comparable to a broken k’li which is no longer susceptible to impurity.

This is the minimum measure for such an article to contract ritual impurity (Hilchot Keilim 23:3).

In Hilchot Mechusrei Kapparah 2:1, the Rambam states that this refers to a man who experiences "[a discharge of] sperm that is released because of an internal sickness that affects the organs [of the body] in which it collects,” a condition somewhat similar to, but by no means identical with, gonorrhea. See Leviticus 15:2.

I.e., for a zav, immersion in a mikveh is not sufficient. See Chapter 9, Halachah 5.

As stated in Hilchot Parah Adumah 6:1, 9-13, this term refers to water that flows from a stream or river that originates in the earth. A stream of rainwater is not acceptable.

“[A woman] who experienced [uterine] bleeding for three consecutive days at a time other than the days when she usually menstruates” (Hilchot Mechusrei Kapparah 1:6; Leviticus 15:25).

Even garments that contracted impurity from a zav.

They may, however, immerse or be immersed in a stream as well. See Hilchot Issurei Bi’ah 11:16.

See examples of this concept in Hilchot Issurei Bi’ah, ch. 6, Hilchot Metamei Mishkav UMoshav, ch. 5, and Hilchot Parah Adumah 1:14.

I.e., a woman who menstruates is impure for seven days.

As stated in Leviticus 12:2, 5, a woman who gives birth to a male is impure for seven days and one who gives birth to a female is impure for fourteen days. Included in this category is also a woman who miscarries. Afterwards, the woman immerses to regain purity.

After the entire span of days when they are impure has passed.

Hilchot Issurei Bi’ah 4:6. At present, unless there are extenuating circumstances involved, all women immerse at night [see Hilchot Issurei Bi’ah 6:7; Shulchan Aruch (Yoreh De’ah) 197:3-4].

The Ra’avad objects to the Rambam’s ruling and maintains that any woman who need not count seven “spotless” days may immerse from nightfall onward. The Kessef Mishneh maintains that the Rambam would accept the Ra’avad’s statements and mentions only a person with a seminal emission, because such a person is explicitly mentioned in the Torah.

I.e., the Jewish day begins at nightfall. If a man had a seminal emission shortly after nightfall, he may immerse immediately. His status is then that of a t’vul yom (see note 33) until nightfall the following day.

“Toward nightfall” implies before nightfall. The verse is thus indicating that if the person had a seminal emission during the day, he may immerse during the day. Extending that logic, if he has a seminal emission at night, he may immerse immediately afterwards.

When he becomes pure. Between immersion and nightfall the following day, his status is that of a t’vul yom, i.e., he is still considered ritually impure and is forbidden to partake of terumah or sacrificial foods or enter the Temple. The laws regarding the impurity he imparts are, however, somewhat more lenient.

If even the smallest part of a person’s body is not immersed, the immersion is not acceptable.

So there are no intervening substances between their bodies and the water. See Halachah 12.

I.e., even if they immerse their entire bodies, but do so limb after limb, the immersion is invalid.

Thus even if one hair is not submerged in the water, the immersion is invalid. See also Chapter 2, Halachah 15.

This applies to loose-fitting garments worn in the Talmudic era and in the Rambam’s time. There are questions whether this law applies with regard to garments that cling to the body tightly. See Siftei Cohen, Yoreh De’ah 198:56.

I.e., her immersion is accepted after the fact. Moreover, in certain extreme situations, e.g., when there are concerns of modesty, she may immerse in her clothes as an initial preference.

As the Rambam states at the conclusion of ch. 11, this is one of the factors that distinguishes the laws of purity as a chok, a decree above rational comprehension.

There were individuals who would frequently partake of terumah (or consecrated foods). Hence, they were stringent and even when preparing and partaking of ordinary foods would follow the stringencies that apply to terumah (or consecrated foods; see Rashi, Chulin 34a). More discussion concerning this matter can be found in Hilchot She’ar Avot HaTum’ah 9:11, 13:2, et al.

See also Chapter 9, Halachah 17.

The Shulchan Aruch (Yoreh De’ah 198:48) quotes the Rambam’s ruling as halachah. The Rama notes that there are more stringent views and states that, as an initial preference, it is proper that a woman immerse again with the proper intent in such circumstances.

In which water flows from a natural stream.

The Kessef Mishneh interprets the wording used by the Rambam (taken from the Tosefta, Mikveot 8:1) as implying that the person must be checked to see that in fact the water covered his entire body.

Initially, in his Kessel Mishneh, Rav Yosef Caro quotes a responsum of Rivosh (Responsum 293) who explains that such conduct is undesirable, because it will create an impression that one is jumping into the water to cool off and not with the intent of immersing himself for the sake of purification. Afterwards, he offers a second explanation, based on the tractate Derech Eretz Zuta, ch. 10: this is speaking about a mikveh with exactly 40 se’ah and if the person jumps in, it is likely that some of the water will splash out and the mikveh will lack its minimum measure. This is the rationale Rav Yosef Caro quotes in his Shulchan Aruch (Yoreh De’ah 201:62). See also Kallah Rabati, ch. 10, which offers other rationales for this and the following laws.

The Rivosh (Responsum 293) states that the rationale is that since he is not immersing in the desired fashion, it appears that he is not immersing with the intent of purifying himself. In his Kessef Mishneh and his Shulchan Aruch (Yoreh De’ah 201:62), Rav Yosef Caro explains that this also is speaking about an instance where the mikveh has only 40 se’ah. It is possible that the first immersion was not performed properly, because he was relying on the second one and it is possible that the second immersion was not acceptable because some water flowed out of the mikveh during the first immersion (Turei Zahav 201:76).
It must be noted that it is customary in many communities for women and men to immerse more than once for a multitude of halachic and mystic reasons. See Ba’er Heiteiv (Yoreh De’ah 200) who states that a woman should immerse once before reciting the blessing and once, afterwards.

Here also the same two approaches are taken. The Rivosh explains that this creates an impression that one is not immersing for the sake of purification. Rav Yosef Caro [in his Kessef Mishneh and Shulchan Aruch (Yoreh De’ah 198:29)] states that this is speaking about a mikveh with just 40 se’ah and we are afraid that the insertion of the other person’s hand will cause some water to flow out of the mikveh. See also Chapter 2, Halachah 11, which states that a person should not hold onto a person who is immersing unless he dips his hand in the mikveh water first.

E. g., his mouth, the inside of his ears, nose, or the like [the Rambam’s Commentary to the Mishnah (Mikveot 8:5)].

For this reason, a woman must clean her teeth before immersion [Shulchan Aruch (Yoreh De’ah 198:24)]. Similarly, a bandage placed in these parts of the body disqualifies an immersion (ibid.:43).

Nidah 66b.

If a woman did not rinse these portions of her body before immersion, but no intervening substance was discovered afterwards, the immersion is acceptable [Shulchan Aruch (op. cit.:25)].

When performing these activities, her limbs are spread slightly, enabling water to reach under her arms and between her legs. See Hilchot Tum’at Tzara’at 9:12; Shulchan Aruch (op. cit.:35).

Or at a beach or any other public place.

Nidah 67a relates that the father of the Sage Shmuel would erect mats to enable his daughters to immerse in the harbor. Other commentaries explain that the mats served different purposes.

It is suspected that out of fear, she will not immerse properly. This is one of the interpretations given in Nidah 66b. Another interpretation is that our Sages forbade such an immersion lest a woman sit on a wooden bench in a bath and immerse herself. The difference between these interpretations is the ruling after the fact, i.e., if a woman immersed herself while standing on such an article. According to the first interpretation, if the immersion was carried out properly, it is acceptable. According to the second interpretation, if she immersed when standing on wooden keilim whose outer surfaces are susceptible to impurity, there is reason to say that the immersion is not acceptable. (Since the outer surface of an earthenware container is not susceptible to impurity, if she immersed while standing on such a surface, the immersion is certainly acceptable after the fact.) Rav Yosef Caro discusses this matter at length in his Kessef Mishneh. In his Shulchan Aruch (Yoreh De’ah 198:31), he rules that, after the fact, even if a woman stood on a wooden k’li, the immersion is acceptable. The Turei Zahav 198:31 and the Siftei Cohen 198:43 discuss this ruling and mention more stringent views.

This halachah serves as an introduction to the following two chapters. In Chapter 2, the Rambam discusses substances that intervene between a person’s flesh and the waters of a mikveh. And in Chapter 3, he discusses substances that intervene between a k’li and the water.

When stating these laws, the Shulchan Aruch (Yoreh De’ah 198:1) uses slightly different wording, stating: “If the way of people is that sometimes they object, it is considered as an intervening substance.” The implication is that the ruling is not dependent on the feelings of the person alone, but it is dependent also on the norm accepted in the society. Thus if there are people who object to such a substance and the person objects, it is considered as an intervening substance. Similarly, if most people object, but the person does not object, it is considered as an intervening substance. It is only when only a few people object and this person does not object that it is not considered as intervening (Turei Zahav 198:2).

Nevertheless, as an initial preference, one should not immerse even when the substance is of the type to which no one would object.