Incubation refers to the amount of time required in a developmental period. It stems from the Latin root incubare, which means to lie upon. This correlates with the term’s most common use today, avian incubation. However incubation can also be applied to chemistry, microbiology, medicine, and even ritual.
Avian incubation denotes the time when the parent birds, usually female, sit upon their eggs. The body heat from the parent provides warmth to the growing eggs and maintains a consistent environment, providing constant humidity, shade, and temperature. Some species of bird, such as mega- podes, incubate their eggs by burying them, with the eggs receiving warmth from geothermal heat and organic breakdown of vegetable matter. The incubation period varies from species to species, ranging from only 11 days up to 85 days. Some species may also begin incubating at different times of development to either stagger the brood’s growth or create a simultaneous hatching.
In chemistry and biochemistry, incubation is the period of time and set of conditions required to maintain a chemical reaction. These condition constants can include temperature, pressure, concentration of reactants and products, and the presence and concentration of a catalyst. By utilizing the proper chemical incubation period, chemists are able to synthesize the highest yield of products in the shortest time.
In medicine, or more specifically pathology, incubation is the amount of time before a patient begins showing symptoms after a pathogen or disease-causing bacterium enters the body. This is often also referred to as the latency period. This incubation period varies for each disease and can range from a few minutes to several years. Generally the incubation period in children is shorter than the incubation period in adults.
Because these diseases are caused by pathogenic organisms, a valuable tool for diagnosing these illness are cultures, including blood, stool, urine, and sputum cultures. These cultured samples are actually grown in optimal conditions in machines called incubators, which can range in size from small tabletop units to those as large as rooms. These microbiological incubators can be programmed to simulate highly specific conditions, including carbon dioxide and oxygen levels, humidity, and temperature. Most incubators are programmed to simulate the internal environment in a human, because pathogenic bacteria usually experience optimal growth in these surroundings.
Another form of medical incubation is done in neonatal intensive care units (NICUs). Here, newborns in critical condition are placed in incubators, which are essentially large open warming units. These provide a constant temperature and oxygen level and a relatively clean environment. More advanced incubators may feature monitoring equipment and pressure capabilities, which help keep premature infants’ airways from collapsing. However, this technology has its drawbacks, as newborns in the NICU often experience high noise and light levels, reduced physical contact with humans, and separation from their parents.
In a less scientific sense than the other definitions, incubation may also be applied to the mystical practice of sleeping in a sacred or divine area in hopes of achieving a spiritual enlightenment, whether it be through a dream, vision, experience, or cure. In ancient times, this practice was very common, especially for followers of the Greek deity Asclepius, the demigod of healing and medicine. Several present-day Christian sects and Greek Orthodox monasteries still practice this method of incubation today.
Christopher D. Czaplicki
See also Chemistry; Medicine, History of;
Bergtold, W. H. (1917). A study of the incubation period of birds: What determines their length. Denver, CO: Kendrick-Bellamy.
Hamilton, M. (2006). Incubation: The cure of disease in pagan temples and Christian churches. Whitefish, MT: Kessinger.