Hekla’s essence is the marriage of sycotic overgrowth and syphilitic erosion concentrated in bone, especially the maxillo-mandibular complex. The keynote is periosteal suffering of the face: nodes, exostoses, osteitis, and caries in a tight anatomic field where mechanical function (chewing) must provoke the part repeatedly. This mechanical provocation explains the entire modality schema: worse chewing, worse motion (local), worse touch and cold air, worse at night; better from warmth and firm pressure—steady counter-force calming the over-excitable periosteum [Clarke], [Boericke]. Kingdom signature (mineral) manifests as structure: too much bone (exostosis), bone in the wrong place (node), and bone inflamed (osteitis), with functional flow (lymph, sinus drainage) clogging over thickened foundations [Scholten-style reasoning], [Clarke]. The pace is sub-acute to chronic; outbreaks (gumboil) may punctuate a quietly relentless nodosity. When a fistula opens, or after surgical evacuation, pain reduction is swift—a clinical law across Hekla cases that parallels Silicea’s draining tendency, yet Hekla acts earlier on the bony driver of the suppuration [Clarke], [Boger], [Phatak].
Psychologically, there is no intrinsic constitutional drama; the mind is the voice of the bone. The sufferer is cautious and practical: protective of the jaw, anxious before meals, avoiding cold air, and irritable when pain is stirred (Mind reflects local pathology). Thermal state is chilly-local; the cheek craves wrapping and warmth. Miasmatically, the picture bears sycotic hypertrophy—nodal growth, polypoid mucosa—layered with syphilitic undermining where bone decays and fistulises, an interplay repeatedly attested in the jaw-sinus-gland axis [Sankaran], [Clarke]. Micro-comparisons help focus selection: Calc-fluor. shares exostoses but extends to elastic tissues and enamel; Silicea shares fistulæ and chill but is more systemic and slower; Mezereum shares nightly bone pains but adds cutaneous neuralgias; Fluoric acid shares destruction but is more corrosive; Phosphorus fits necrosis with haemorrhagic diathesis; Mercurius suits septic mouths with salivation; Hekla stands when the bony periosteum itself is sovereign and mechanically aggravated [Clarke], [Boericke], [Boger].
In practice, Hekla is a regional remedy of high value. It does not attempt to “rule the patient” constitutionally; rather, it rules the pathological centre where bone, sinus, tooth, and gland meet. Chosen on these grounds, it often unlocks stubborn maxillofacial conditions and tibial nodes alike, especially when pain exceeds the visible dental defect and palpation finds a tender bony prominence. The physician should expect improvement to track the mechanical story: less tenderness to pressure, mastication tolerated, fistula drying, swelling softening, and sleep returning as the nocturnal pains abate—precisely mirroring the modalities recorded in the materia medica [Clarke], [Boericke].

Hepar sulphuris calcareum is the portrait of reactive fragility: a person whose nerves are bare and whose tissues are itching to suppurate. The hallmark is exaggerated sensitivity—to cold air, to touch, to pain, to contradiction. The slightest draft spasms the larynx into choking cough; a gentle probe is felt as a knife or splinter; a small pustule demands wrapping and warmth. This sensory hyper-algia is not affectation; it is a pathophysiologic trait: sulphide–lime reactivity mirrored in the body as explosive catarrh and pus, fetid and thick, erupting in ears, nose, throat, skin, glands, and anus. The miasmatic blend shows: psora (reactive oversensitivity), sycosis (pus, catarrh, glandular swellings), and syphilis (ulceration and fetor). Hepar’s organism fears exposure; it must be wrapped, kept warm, and left unjarred. Anger is quick—hasty, peevish, ready to scold—yet this is the voice of pain.

The modalities are the prescriber’s compass: worse cold dry wind, worse the least uncovering, worse touch, worse night (2–4 a.m.); better warmth, better moist air, better wrapping, better gentle perspiration. These recur in Mind (irritable when chilled), Throat (quinsy, croup—wrap and warm), Ears/Nose (otitis, fetid sinusitis), Skin (boils, felons), Rectum (fissures/fistulae), and Generalities. The splinter pain is an emblem—wherever Hepar acts, pains feel sharp, stabbing, out of proportion, and exquisitely touch-sensitive.

Stage-direction is central: in early threatened suppuration—a hard, hot, exquisitely tender gland; an angry felon just beginning—Hepar may abort the process, calming, softening, and turning aside pus. But when pus is formed, Hepar can hasten pointing and evacuation, converting a tormenting, subcutaneous pressure into a clean discharge followed by relief—provided the surgeon’s maxim of adequate drainage is respected. This “manage the stage” wisdom separates Hepar from Silica (slower, deeper, less fetid) and from Mercury (sweat-saliva septic storms). The Hepar constitution is a winter creature—cowardly to cold, quick to rage, quick to pus, and quick to convalesce when protected and matched to its similimum. [Hahnemann], [Hering], [Kent], [Clarke], [Boger], [Boericke], [Nash], [Tyler], [Phatak]

Hydrocyanic acid epitomises the medicine of the last breath: the organism halts without warning—breath, heart, consciousness—then seizes a single gasp and fights back to a flicker of life. The themes are abruptness, silence, and reflex excitability. Abruptness: attacks begin and end in an instant, with no prodrome beyond a tremor, a hush, or a child’s fixed stare. Silence: in whooping-cough and laryngismus there is a long, awful pause before any sound; in syncope there is no struggle, only a slack fall or stiffening arc; in angina there is constriction without a cry. Reflex excitability: the slightest noise, touch, or attempt to swallow may throw the medullary switch again, re-arresting breath or launching a convulsion [Hering], [Clarke], [Allen]. Kingdom-wise (inorganic acid), the action is direct, chemical, and central; miasmatically syphilitic, it wreaks arrest and dissolution where other remedies inflame. The modalities frame the essence: worse warm, close rooms; worse least motion, noise, touch; worse swallowing and after eating; better cold air, fanning, head low, quiet, and, paradoxically, gentle warmth to chest/epigastrium as a subjective comfort. These recur in Mind (terror of suffocation), Head (blackness on rising), Throat (glottic and œsophageal spasm), Heart (instant power-failure), Respiration (apnœa → gasp → a few breaths), and Skin (blue, cold, clammy).

Differentially, Hydrocyanic acid must be separated from Carbo-veg. (collapse wants air with gaseous distension and a somewhat steadier rhythm; Carbo-veg. is the chronic asphyxiant, Hydrocy. ac. the explosive one), Laurocerasus (similar cyanosis and need for air but slower, less convulsive, more pulmonary), Camphor (icy, but heat is intolerable and spasm is less), Opium (deep, noisy coma without the prolonged silent pause), and Cuprum (convulsions with more clonic violence and less medullary arrest). In pertussis, Corallium rubrum delivers a torrent of coughs; Hydrocyanic acid delivers a long, terrible pause before a feeble gasp. In angina, Glonoinum throbs and bursts; Hydrocyanic acid grips and stops. The clinical art is to recognise the choreography: the hush, the blue, the gasp, the cold sweat—then to place the patient at a window, cool the room, quiet the surroundings, and give the remedy while supporting with measures that match its modalities [Clarke], [Boericke], [Boger].

In practice, Hydrocyanic acid is invaluable when the respiratory centre forgets its work in paroxysms—infantile laryngismus, asphyxia neonatorum, whooping-cough with long apnœic pauses, epileptiform fits with cyanosis, anginoid collapses, and choleraic sinkings with hiccough—especially in nervous, excitable subjects and in the aged exhausted by chronic catarrh. It is not a fever remedy; it is the medicine of the medulla. Improvement is read not in warmth or appetite first, but in lengthening of intervals, shortening of the silent pause, lessened startle-provoked spasm, and a steadier, quieter breath at night.