Definition
A phrase describing the legal condition of a person who is simultaneously required to perform an act and is also the person upon whom that act operates — that is, one who is both the doer and the receiver of the same transaction or obligation.
The classic illustration is that of an executor who is personally owed a debt by the deceased's estate. In his capacity as executor, he is obligated to satisfy the debts of the estate (the agent, or doer); in his personal capacity, he is the creditor entitled to receive payment (the patient, or receiver). The same individual occupies both roles, and the legal consequence is that he may effectively retain from estate assets the amount owed to him — a form of self-dealing that the law must specially address to avoid circularity.
The phrase is drawn from the Latin distinction between agens (acting) and patiens (receiving or suffering), and it surfaces in contexts where a single person's dual legal roles produce an apparent logical tension: How can one meaningfully pay oneself, sue oneself, or authorize oneself in two different capacities?
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Common Language
Modern common usage (Wiktionary): "Agent" in ordinary English means a person who acts on behalf of another, or more broadly, any entity that takes action. "Patient" in ordinary English means one who receives medical care, or more broadly, one who endures or suffers something.
Historical common usage (Webster's 1913): "Agent" — one who acts or exerts power; one who acts for another by authority. "Patient" — one who receives impressions from external agents; a person or thing that receives the action of another.
The gap matters here. In ordinary English, "agent" and "patient" are simply opposites — one acts, the other receives. The legal phrase deliberately fuses these opposites into a single person, capturing a specific juristic problem: when the same individual occupies both active and passive legal roles in the same transaction, ordinary rules of obligation and authorization require modification. The common meanings of the words, taken separately, would obscure the doctrinal point entirely.
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Common Confusion
Do not confuse this phrase with the general law of agency, which governs the principal-agent relationship. "Agent and patient" is a narrow term of art describing a specific structural condition — dual legal roles converging in one person — rather than a description of an agent's function or authority. A researcher encountering this phrase in older case law or treatise text should not read it as commentary on the scope of an agent's authority or the duties running between agent and principal.
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Why It Matters in Research
This phrase is archaic in modern legal writing and will appear almost exclusively in historical sources — early American case law, English common law materials, and the foundational treatises. Researchers should treat it as a signal pointing toward one of several recurring legal problems that the phrase historically labeled but that modern law addresses under other terminology.
When encountered in older probate and estate materials, the phrase typically signals the executor-creditor problem: the same person owes duties to the estate while holding personal claims against it. Modern law resolves this through executor accounting requirements, conflict-of-interest rules, and the doctrine of retainer or appropriation in estates practice.
When encountered in corporate or agency materials, the phrase anticipates problems now treated under self-dealing doctrine, the duty of loyalty, and conflicts of interest for fiduciaries and agents.
The Rapalje & Lawrence entry distinguishes the phrase sharply from the broader discussion of "agent" and notes the dual-role condition without extended analysis, which is typical — most historical dictionaries treat this as a passing definitional note rather than a developed doctrine. Researchers should not expect to find "agent and patient" as a doctrinal heading in case law indexes; the condition it describes will instead appear under the substantive topics listed above.
The maxim cited in Black's — agentes et consentientes pari poena plectentur (acting and consenting parties are liable to the same punishment) — is a distinct principle from "agent and patient" and refers to joint liability in criminal or quasi-criminal contexts. The two concepts share vocabulary but are unrelated doctrines. The proximity of the maxim to the "agent and patient" definition in Black's can mislead a researcher into treating them as connected.
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Historical Dictionary Support
All four source dictionaries agree on the core definition: "agent and patient" describes a person who is both doer and receiver in the same legal transaction. Burrill and Bouvier provide the most useful elaboration, with Bouvier offering the executor-creditor example that anchors the phrase to concrete practice. Burrill adds the executor-retainer illustration — an executor who keeps estate funds in satisfaction of a personal debt — which is functionally the same scenario from a slightly different angle.
Rapalje & Lawrence compress the definition to a single line, reflecting the phrase's limited standalone doctrinal significance by the late nineteenth century. Black's reproduces the standard definition and appends the Latin maxim, a pairing that appears more organizational than substantive.
Bouvier's secondary entry — distinguishing an agent from a broker in real estate contexts — is not a definition of "agent and patient" as a phrase but rather a general note on the law of agency. It should not be read as elaborating the dual-role doctrine. Its inclusion in the same entry appears to be an artifact of editorial organization rather than conceptual connection.
None of the historical dictionaries develops the phrase beyond illustration. No treatise treatment of "agent and patient" as a freestanding doctrine exists in the standard sources; its significance lies in identifying the problem, not in establishing a body of rules. The doctrinal work is done elsewhere, under executors, fiduciaries, and self-dealing.
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Encyclopedia Cross-Reference
The Law Mind Business Organizations & Corporate Law Encyclopedia:
- Agency — Authority of Agents (Actual, Apparent, and Inherent)
- Agency — Duties of Principals to Agents
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