Olfactory Acuity (sage ability)

Olfactory Acuity is an amateur-status sage ability in the study of Mosses & Ferns, providing the ability to perceive and interpret odours with unusual sensitivity, so as to judge the condition of living bodies and the nature of substances by scent. Through this faculty, the character may detect changes not readily apparent to sight or touch, recognising the presence of corruption, imbalance or alteration in a patient, as well as the general character of preparations that act upon the body, such as poisons, salves and potions.

As the character advances from amateur to authority and beyond, this acuity becomes more refined, permitting the recognition of fainter odours and the distinction between conditions that would otherwise seem alike. What is first perceived as a general taint or quality comes to be understood in more exact terms, so that the character may judge not only the presence of a condition, but its nature, degree and likely course.

Leaving a Scent

For a scent to endure in an area, the source of the odour must remain in one place for at least half an hour. This condition is readily met by diseases of the body, or by the presence of feces or urine, which, once deposited, persist for some time. Moving creatures do not ordinarily leave such a trace; a single orc passing through a tunnel, for example, would not produce an odour that could be reliably detected once it has gone.

That said, if an area is used repeatedly by orcs as a place of relief, the accumulation of their presence may allow the character to distinguish not merely the smell of urine, but that it is specifically orc-derived. From this, the character may recognise the presence of orcs in the vicinity, or identify rooms where they have habitually gathered. Where objects used by a creature are present, such as bedding, cups or tables, these may likewise be examined, as they retain the odour of those who have handled or occupied them.

Sniffing the Air

To capture a scent from an ailing person or from the general ambient air, the character must close their eyes and draw two deep breaths, then remain still while attending to whatever odour presents itself. This act of concentration requires 2–5 rounds. If a roll for surprise is required during this time, the character is considered to have failed it automatically; it is therefore advisable that companions remain on guard while the effort is undertaken.

When sniffing the air, something will always be smelled, even if only dust or the general taint of the air itself. From this, Success that something will be smelled is assured, if only dust or the taint of the air itself. Other smells that emerge can be separated by the character, but only the two strongest — those most easily detected on the table below — can be identified. To grasp more subtle odours, characters must take steps to isolate an area by clearing it of stronger odours, perhaps by cleaning, freshening the air or otherwise neutralising competing smells. Because of this, practitioners will often take steps to clear lingering odours before making an assessment. Though soap is not commonly employed for this purpose, surfaces may be washed with water or tables sluiced between examinations, so that the scent of one patient does not interfere with that of the next.

Once an odour is identified, the character may hold to it, keeping that scent distinct from others so long as attention is maintained. This allows the source to be tracked, compared against nearby impressions or used to judge changes in the same subject over time, provided the air is not so disturbed as to disperse it. Thus, once a character has identified that orcs have passed through an area, the direction of their movement may be judged by proceeding towards where the scent is strongest, allowing a form of tracking. If the trail crosses ground where the orcs have not lingered, however, the character is not the equal of a bloodhound; the scent is lost, and with it the benefit of the sage ability.

Olfactory Perception Table

The list below is not to be considered exhaustive; as this rule is newly introduced, continued play will reveal additional creatures that ought to be included. Revisions may be made as needed. For the present, sufficient examples are provided to guide the placement of unlisted cases.

Olfactory Perception

Status	Disease Types	Severity	Corruptions	Creatures	Poisons & Venoms	Potions
amateur	blood, breathing, sinuses, skin, stomach & colon	presence	charring, fecal, injury, intoxication, spoiled food, urine, vomit, wound	canines, ghast, goblinish, half-orcs, orcish, rodents, troglodytes, ursine	presence of venom	extra-healing, healing, sweet water
authority	bladder, muscles, joints, heart, hormonal	nature	addiction, dehydration, fever, gangrene, necrosis	dwarves, gnomes, felines, humans	biliosis, ictus, somnikus, vexation; venoms that cause paralysis, tissue damage, heart failure	climbing, fire resistance, flying, growth, heroism, longevity, poison potion, speed, super-heroism, water breathing
expert	ears, eyes, skeletal	degree	battlefield injury, death by poison	avians, beasts, elves, giants, half-elves, halflings, lycanthropes, slimes, undead	carroder, suurbite, whisperbane; spider, snake, scorpion	all control potions, all oils, all philters, clairaudience, clairvoyance, delusion, ESP, levitation
sage	brain & nerves		death by magic	dragons, magic-based creatures	everything relevant to the venom	diminution, gaseous form, giant strength, invisibility, invulnerability, polymorph self, treasure finding

Disease Types are organised by the part of the body affected, reflecting the manner in which odours arise from specific systems and functions. The odour arises from the body itself, as disease alters its ordinary processes and produces byproducts that are carried outward. These are released through the breath, the skin and the various discharges of the body, so that even conditions deep within will manifest as a scent. The incorrectness of the odour allows the physician to judge, by its character, which part of the body is likely affected; where the scent does not conform to any known type, that unfamiliarity itself serves to exclude possibilities, helping to sort what the disease is not.

While amateurs and detect the presence of the disease they know, authority-status characters can also detect the nature of the disease — that is, whether it is acute or chronic. Experts and sages can do better, determine the probable severity of the disease detected, by smell alone, regarding whether or not it is mild, severe or terminal. However, in either deducing nature or severity, there is an inexactness of this; the actual disease condition may deviate by as much as two points, plus or minus, from the olfactory's guess. Thus, if the severity of the disease were guessed to be a 5 out of 8 by odour, the actual severity could be anywhere, randomly, from 3 to 7.

In some cases, such as a disease of the bladder, where the disease is acute 1-6 out of eight, then an olfactory guess of 1 would be sufficient to be certain that this specific case was in fact acute. Likewise, if an 8 were rolled for heart disease's severity, indicating a terminal case, a deviation of 2 is not sufficient to allow the possibility for survival, since any roll from 5-8 on the severity table for that disease indicates death. This occasionally allows cases where the smell indicates a condition that is unmistakable.

Corruptions are intrusive smells that are direct expressions of burnt refuse, waste, systemic imbalances that alter the body's output, exposed tissue and decay, or outright tissue death. Addiction sits slightly differently, but still fits as a persistent alteration of the body's state that produces a recognisable taint. Some of these can be detected after death has occurred; for example, the character might be able to tell that a body was wounded before it died, or that the corpse was addicted to a specific substance, particularly tabacco or alchohol. This may be useful if investigating a death is a matter before the party.

Creatures provides, at best, a generalised guideline, as an attempt to include every monster would be impractical. "Goblinish" includes hobgoblins, bugbears, norkers and other groups, possessing a strong acrid odour, which to most having this skill will smell alike — however, a gnome will be able to distinguish a difference between them. Similarly, "orcish" peoples include haruchai, cavewights and ogres, which are likewise indistinguishable except to dwarves. Undead cannot be distinguished from one another unless the character has experienced a trauma of some sort at the hands of one kind (having been died and raised, being trapped with same for at least four hours, having nearly succumbed to transformation and the like). Avians, beasts, giants or dragon types cannot be separately identified.

Poisons, Venoms & Potions can be certainly identified for what they are by safely bringing the substance, normally in some sort of container, near enough to the nose. No saving throw is necessary. Poisons that cause "tissue damage" have effectst that deplete hit points; those that cause "heart failure" have save-or-die effects.