Embden-Meyerhof-Parnas pathway See glycolysis
embezzlement Crime of fraudulently appropriating property entrusted to one’s care and converting it to one’s own use. It occurs when a person gains possession of goods lawfully and then misappropriates them. It thus stands in contrast to larceny, the taking of goods from another without the latter’s consent. The most widely adopted embezzlement statutes cover custodians of public funds. Many laws subject public servants to severe penalties, even if funds are lost through improper administration rather than a clear attempt to steal. See also fraud, theft.
embolism Vem-bs-.li-zsnA Obstruction of blood flow by an embolus— a substance (e.g., a blood clot, a fat globule from a crush injury, or a gas bubble) not normally present in the bloodstream. Obstruction of an artery to the brain may cause stroke. Pulmonary embolism (in the pul¬ monary artery or a branch) causes difficulty breathing, chest pain, and death of a section of lung tissue, with fever and rapid heartbeat. Embo¬ lism in a coronary artery can cause heart attack. See also thrombosis.
embroidery Art of decorating textiles with needle and thread. Among the basic techniques are cross-stitch, crewel work, and quilting. The Per¬ sians and Greeks wore quilted gar¬ ments as armor. The earliest surviving examples of embroidery are Scythian (c. 5th-3rd century bc).
The most notable extant Chinese examples are the imperial silk robes of the Qing dynasty (1644-1911/12).
Islamic embroideries (16th-17 th century) show stylized geometric patterns based on animal and plant shapes. Northern European embroi¬ dery was mostly ecclesiastical until the Renaissance. European skills and conventions prevailed in North America in the 17th—18th century.
The Native Americans embroidered skins and bark with dyed porcupine quills; later the beads they acquired in trade took the place of quills. The indigenous peoples of Central America produced a kind of embroidery with feathers. The Bayeux Tapestry is the most famous surviving piece of needlework.
embryo \'em-bre-,o\ Early stage of development of an organism in the egg or the uterus, during which its essential form and its organs and tis¬ sues develop. In humans, the organism is called an embryo for the first seven or eight weeks after conception, after which it is called a fetus. In mammals, the fertilized egg or zygote undergoes cleavage (cell division without cell growth) to form a hollow ball or blastocyst. During the sec¬ ond week following fertilization, gastrulation (cell differentiation and migration) results in the formation of three tissue types. These three types of tissue develop into different organ systems: the ectoderm develops into the skin and nervous system; the mesoderm develops into connective tis¬ sues, the circulatory system, muscles, and bones; and the endoderm devel¬
ops into the lining of the digestive system, lungs, and urinary system. In humans, by about the fourth week, the head and trunk can be distinguished and the brain, spinal cord, and internal organs begin to develop. By the fifth week, limbs begin to appear and the embryo is about .33 in. (.8 cm) long. By the end of eight weeks, the embryo has grown to about 1 in. (2.5 cm) long and all subsequent change is limited primarily to growth and specialization of existing structures. Any congenital disorders begin in this stage. See also pregnancy.
embryology Study of the formation and development of an embryo and fetus. Before widespread use of the microscope and the advent of cellular biology in the 19th century, embryology was based on descrip¬ tive and comparative studies. From the time of Aristotle it was debated whether the embryo was a preformed, miniature individual or an undif¬ ferentiated form that gradually became specialized. The latter theory was proved in 1827 when Karl Ernst Baer discovered the mammalian ovum (egg). The German anatomist Wilhelm Roux (1850-1924), noted for his pioneering studies on frog eggs (from 1885), became the founder of experimental embryology.
'Emeq Yizre'el See Plain of Esdraelon
emerald Grass-green variety of beryl that is highly valued as a gem¬ stone. Its physical properties are those of beryl. Its refractive and disper¬ sive powers (i.e., its capacity to deflect light and to break white light into its component colours) are not high, so cut stones display little brilliancy or fire (flashes of colour). The colour that gives this gem its value is due to the presence of small amounts of chromium. The most important pro¬ duction of fine quality gem material is from Colombia; emeralds are also mined in Russia, Australia, South Africa, and Zimbabwe. Synthetic emer¬ alds are identical to natural crystals and may rival them in colour and beauty.
emergence In the theory of evolution, the rise of a system that cannot be predicted or explained from antecedent conditions. The British philosopher of science G.H. Lewes (1817-78) distinguished between resultants and emergents—phenomena that are predictable from their constituent parts (e.g., a physical mixture of sand and talcum powder) and those that are not (e.g., a chemical compound such as salt, which looks nothing like sodium or chlorine). The evolutionary account of life is a continuous history marked by stages at which fundamentally new forms have appeared. Each new mode of life, though grounded in the conditions of the previous stage, is intelligible only in terms of its own ordering principle. These are thus cases of emergence. In the philosophy of mind, the primary candidates for the status of emergent properties are mental states and events.
Emerson, P(eter) H(enry) (b. May 13, 1856, Cuba—d. May 12, 1936, Falmouth, Eng.) English photographer. Trained as a physician, he began using photography in an anthropological study of East Anglia; the images were published in several books. A proponent of photography as a medium of artistic expression, he published a handbook, Naturalistic Photography (1889), in which he outlined his aesthetic system (“natural¬ ism”), emphasizing that photographs should look like photographs rather than paintings. The book was so popular that he became known as one of the world’s leading photographers, and his views influenced much of 20th-century photography.
Emerson, Ralph Waldo (b.
May 25, 1803, Boston, Mass.,
U.S.—d. April 27, 1882, Concord)
U.S. poet, essayist, and lecturer.
Emerson graduated from Harvard University and was ordained a Unitarian minister in 1829. His questioning of traditional doctrine led him to resign the ministry three years later. He formulated his phi¬ losophy in Nature (1836); the book helped initiate New England Tran¬ scendentalism, a movement of which he soon became the leading exponent. In 1834 he moved to Concord, Mass., the home of his friend Henry David Thoreau. His lectures on the proper role of the scholar and the waning of the Christian tradition caused consid-
Detail of an embroidered waistcoat, French, 1800-25; in the Metropolitan Museum of Art, New York City
COURTESY OF THE METROPOLITAN MUSEUM OF ART, NEW YORK CITY, GIFT OF UNITED PIECE DYE WORKS, 1936
Ralph Waldo Emerson, lithograph by Leopold Grozelier, 1859
COURTESY OF THE LIBRARY OF CONGRESS, WASHINGTON, D.C.
© 2006 Encyclopaedia Britannica, Inc.
618 I emery ► emperor
erable controversy. In 1840, with Margaret Fuller, he helped launch The Dial, a journal that provided an outlet for Transcendentalist ideas. He became internationally famous with his Essays (1841, 1844), including “Self-Reliance.” Representative Men (1850) consists of biographies of historical figures. The Conduct of Life (1860), his most mature work, reveals a developed humanism and a full awareness of human limitations. His Poems (1847) and May-Day (1867) established his reputation as a major poet.