A brief examination of the history of classification will serve as a reference point for nursing classifications. It is sometimes stated that the idea of classification dates back to the book of Genesis. Out of chaos "God divided the light from darkness." Primitive cultures, as well as more advanced societies, have classified health-related ideas important to the culture. In his studies of world cultures Murdock (1980) classified theories of illness into theories of natural causation and theories of supernatural causation. (Information for Murdock's subcategories listed in Table 1 are based on information from pages 8-20 of his book.) The Hippocratic School of ancient Greece explained disease using the concept of "humors" rather than supernatural or magical forces.

TABLE 1.
Classification of Theories of Illness
Worldwide Theories of Illness
A. Natural Causation	B. Supernatural Causation
Type 1. Infection	Type 6. Fate
Type 2. Stress	Type 7. Ominous Sensations
Type 3. Organic deterioration	Type 8. Contagion
Type 4. Accident	Type 9. Mystical Retribution
Type 5. Overt Human Aggression

The first systematic attempt to classify disease is credited to Francois Bossier de Lacroix with the publication of Nosologia Methodica in the mid-1700s. Interest in the 18th and 19th century centered on the classification of causes of death, although many thought the classification should also include non-fatal conditions. Florence Nightingale delivered a paper titled Proposals for a Uniform Plan of Hospital Statistics at the fourth International Statistical Congress in London, 1860, urging the inclusion of non-fatal conditions.

By 1893 the International Classification of Diseases and Causes of Death was being used and in 1946 the World Health Organization (WHO) assumed responsibility for reviewing and revising this system every 10 years. The WHO recommended that countries establish national committees on vital and health statistics in 1948 to encourage international cooperation and to be used as a resource by WHO for future revisions of the classification (Zernott, 1982). This structure for international cooperation in classification system development has many similarities to that which is evolving in nursing.

Similarities exist also between nursing and medicine in the number of classification systems with different foci. In medicine morbidity and mortality statistics are compiled using the International Classification of Diseases (ICD). The ICD is adapted for the United States and has been further adapted for hospitals' statistical reports (H-ICDA). For example, in the United States the category "chronic ulcer of the skin" has been differentiated into "decubitus ulcer" and "leg ulcer." Other countries have other needs for specificity. In an international, nursing classification system, adaptations, such as these, will occur when a country wishes more or less specificity, relative to epidemiology or cultural needs.

Some of the other nomenclature systems used in medicine include Standard Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), International Classification of Injuries, Disabilities, and Handicaps (ICIDH), Standard Nomenclature of Disease and Operations (SNODO), Systematized Nomenclature of Pathology (SNOP), and Systematized Nomenclature of Medicine (SNO MED III). As may be noted from the names, classification systems are designed for specific purposes to meet the needs of particular users. The idea of systems for specific purposes is also a trend in nursing classification; there are systems which are multipurpose and systems for particular settings, such as home care nursing.