Arndt–Schulz rule or Schulz' law is a claimed

law Law is a set of rules that are created and are enforceable by social or governmental institutions to regulate behavior, with its precise definition a matter of longstanding debate. It has been variously described as a science and as the ar ...

concerning the

effects Effect may refer to: * A result or change of something ** List of effects ** Cause and effect, an idiom describing causality Pharmacy and pharmacology * Drug effect, a change resulting from the administration of a drug ** Therapeutic effect, ...

of pharmaca or

poisons A poison is any chemical substance that is harmful or lethal to living organisms. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figurati ...

in various concentrations. It states that: That is to say, highly diluted pharmaca or poisons enhance

life processes ''Life Processes'' is the second album by ¡Forward, Russia!, and was released in the UK on 14 April 2008. It was produced by former Minus the Bear keyboardist Matt Bayles at Red Room Recordings in Seattle, Washington. The first single from the ...

, while strong concentrations may inhibit these processes and even terminate them. The rule was named after Hugo Paul Friedrich Schulz and

Rudolf Arndt Rudolf Gottfried Arndt (31 March 1835 – 29 January 1900) was a German psychiatrist from Bialken, district of Marienwerder. Biography Arndt studied in Greifswald and Halle. As a student, his instructors included Felix von Niemeyer (182 ...

. The latter originally formulated it in 1888. However, the exceptions to the rule are so numerous that it can not be considered a general law. For instance, many paralysing substances have no exciting effect in weak doses, and what constitutes a weak, medium, or strong stimulus is highly individual, as pointed out by Arndt himself. The rule is no longer cited in modern

pharmacology Pharmacology is the science of drugs and medications, including a substance's origin, composition, pharmacokinetics, pharmacodynamics, therapeutic use, and toxicology. More specifically, it is the study of the interactions that occur betwee ...

texts, having been supplanted by the theory of

hormesis Hormesis is a two-phased dose-response relationship to an environmental agent whereby low-dose amounts have a beneficial effect and high-dose amounts are either inhibitory to function or toxic. Within the hormetic zone, the biological response to ...

Scientific basis for homeopathy

This rule has been claimed by some

homeopath Homeopathy or homoeopathy is a pseudoscientific system of alternative medicine. It was conceived in 1796 by the German physician Samuel Hahnemann. Its practitioners, called homeopaths or homeopathic physicians, believe that a substance that ...

s as supporting their hypotheses. However, this rule does not apply to the extremely high dilutions typically used by homeopaths, which have a high probability of containing no molecules of the diluted substance. To explain the purported therapeutic powers of homeopathic remedies (only for ultra high dilutes)

Jacques Benveniste Jacques Benveniste (; 12 March 1935 – 3 October 2004) was a French immunologist born in Paris. In 1979, he published a paper on the structure of platelet-activating factor and its relationship with histamine. He was head of allergy and inflamma ...

created the postulate of "

water memory Water memory is the purported ability of water to retain a memory of substances previously dissolved in it even after an arbitrary number of serial dilutions. It has been claimed to be a mechanism by which homeopathic remedies work, even when t ...

". The water memory hypothesis defies conventional scientific understanding of

physicochemical Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mecha ...

knowledge through which the perceived effect of a chemical compound after its removal from a solution is not expectable due to the assumption ''no molecules, no effect''.

Historical perspective

Early studies of how living systems react to stimuli showed that physiological responses could be obtained with some regularity upon exposure to defined doses. Devising a mechanism for these observations proved difficult, and a significant amount of scientific effort was expended on the subject. The work of

Arndt Arndt or Arnd is a German masculine given name, a short form of Arnold, as well as a German patronymic surname. Notable people with the name include: Given name *Arndt Bause (1936–2003), German composer of popular songs * Arndt von Bohlen und ...

and Schultz, along with that of

Ernst Heinrich Weber Ernst Heinrich Weber (; ; 24 June 1795 – 26 January 1878) was a German physician who is considered one of the founders of experimental psychology. Ernst Weber was born into an academic background, with his father serving as a professor at t ...

and

Gustav Theodor Fechner Gustav Theodor Fechner (; ; 19 April 1801 – 18 November 1887) was a German physicist, philosopher, and experimental psychologist. A pioneer in experimental psychology and founder of psychophysics (techniques for measuring the mind), he inspired ...

, was called upon to provide some explanation for the observed relationships between dose and response during the early days of pharmacology. However, the concepts Hormesis and Receptor Theory eventually supplanted such "laws" as a more complete and well-defined means of describing how chemicals and physiological systems interact.

References

{{DEFAULTSORT:Arndt-Schulz Rule Eponymous chemical rules Homeopathy

Scientific basis for homeopathy

Historical perspective

See also

References