Definition
Intromission has two distinct legal meanings depending on jurisdiction and context.
1. (Scots law) The assuming of possession or management of property belonging to another person, whether done on lawful authority or without it. Lawful intromission arises where a person has legal grounds to take custody of another's property — for example, as executor, trustee, or spouse preserving a deceased partner's estate. Unauthorized intromission, committed without legal title or authority, is termed vitious (or vicious) intromission and carries serious consequences: a person who irregularly intermeddles with the effects of a deceased person may be held liable for the whole of the deceased's debts, not merely the value of the property handled.
2. (English law and agency contexts) The dealing with stocks, goods, or cash belonging to a principal that come into the hands of an agent, creating an obligation to account to the principal. In this sense, intromission describes the transactional relationship between fiduciary and beneficiary — the agent's receipt and handling of property not their own.
Common Language
Modern common usage (Wiktionary): Insertion of one thing into another; admission or entry; also (in contemporary usage) the initial penetration in sexual intercourse.
Historical common usage (Webster's 1913): The act of sending or putting in; insertion; the act of letting go in; admission; and also, intermeddling with the affairs of another.
The gap between common and legal meaning is significant in one direction: the physical senses of the word (insertion, admission of persons) bear no relationship to either legal meaning. The legal concept centers on unauthorized or authorized interference with another's property or assets, a meaning that Webster's captures in its third definition but that modern general usage has largely abandoned in favor of anatomical connotations. A researcher encountering the word in a historical legal text should not import any physical-entry meaning.
Common Confusion
Intromission is sometimes read as a synonym for simple possession or receipt of property. The distinction matters: lawful intromission carries fiduciary obligations and accountability, while vitious intromission triggers liability beyond the value of the property taken. The two forms share the same name but produce opposite legal postures — one sanctioned by law, the other a quasi-delict. Researchers should also note that the English agency usage (dealing with a principal's property) is related conceptually but not identical to the Scots law doctrine; the Scots framework, particularly vitious intromission, has no direct English common law counterpart.
Recognized Forms
/SUBTYPES
Vitious (Vicious) Intromission: The unauthorized or irregular intermeddling with the effects of a deceased person. Under Scots law, this subjects the intromitter to liability for the entirety of the deceased's debts — a penalty that historically exceeded mere disgorgement. Kames treats this doctrine at length in his work on Scots equity.
Necessary Intromission (Nece Intromission): A recognized exception under Scots law where a surviving spouse continues in possession of the deceased spouse's goods for purposes of preservation rather than appropriation. The possession is justified by necessity and carries no punitive consequence.
Lawful Intromission: Possession or management of another's property taken on legal authority — as executor, trustee, or authorized agent — with corresponding duties of accounting.
Why It Matters in Research
Intromission is a term of primarily Scots law provenance, and researchers working with English common law sources will find it only in the narrower agency-accounting context. Conflating the two usages across jurisdictions is a common error.
In historical Scots legal materials, the doctrine of vitious intromission was a live and consequential rule well into the eighteenth and nineteenth centuries; the Kames citation appearing across multiple dictionary sources signals that Kames' Equity is the primary analytical source and should be consulted directly for doctrinal depth. The dictionary entries themselves are thin on the mechanics — they identify the consequence (liability for the whole debts) without explaining the underlying rationale or the procedural means of establishing it.
The necessary intromission subtype appears only in Black's (both editions) and is absent from several other dictionary sources, which means researchers relying solely on Bouvier or Burrill may miss a critical defense available to surviving spouses in Scots estate disputes.
For the English agency usage, Bouvier's citation to 29 Eng. Law & Eq. 391 is the most specific pointer in the historical dictionary corpus; Anderson's entry is the most practically oriented, framing intromission as an accounting obligation. Researchers in principal-agent disputes should treat intromission in English sources as synonymous with receipt-and-accountability — the focus is on the duty to account, not on the manner of acquisition.
The word's modern retreat from general legal vocabulary (outside Scotland) means it will appear more frequently in nineteenth-century treatises and digests than in contemporary materials. In corpus searching, be alert to spelling variants: vitious and vicious both appear in authoritative sources.
Historical Dictionary Support
The historical dictionaries are in close agreement on the Scots law definition: all sources that address intromission substantively — Black's, Black's 2nd, Burrill, Bouvier, and Rapalje — converge on the formulation of "assuming possession of property belonging to another, on legal grounds or without authority." The phrasing tracks closely to Bell's Dictionary of Scots Law (cited by Bouvier) and Kames (cited by Black's and Burrill), indicating the dictionary compilers drew from a common and reliable doctrinal source.
Anderson's Dictionary of Law is the outlier: it addresses only the English agency meaning and omits the Scots doctrine entirely, reflecting a practitioner-oriented focus on English commercial law rather than comparative or historical coverage.
The historical sources collectively underperform on necessary intromission. Only Black's (both editions) mentions it, and those entries are brief. Wharton is cited but not quoted. Researchers relying on Bouvier or Burrill alone will find no discussion of the necessary intromission defense.
No historical dictionary entry adequately addresses the procedural consequences of vitious intromission — the mechanism by which a creditor could invoke the doctrine against an irregular intromitter. For that, primary Scots legal sources and Kames' Equity are essential.
Jurisdictional Note
Intromission as a doctrinal term is principally operative in Scots law, where it retains historical significance in succession and estate administration. In English and American law, the term appears in agency and fiduciary contexts but has largely been displaced by more familiar vocabulary (receipt, conversion, accounting). Researchers working in Canadian or South African legal history may encounter the term in sources influenced by Scots legal tradition.