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Pettenkofer, Max von

(Encyclopedia)Pettenkofer, Max von mäks fən pĕtˈənkōˌfər [key], 1818–1901, German chemist and hygienist. He studied medicine at Munich. Pettenkofer is considered a founder of epidemiology and is known for...

chinch bug

(Encyclopedia)chinch bug, small North American bug, Blissus leucopterus, of the seed bug family. It feeds on small grains, corn, and other grasses, sucking the plant juices and doing much damage to crops, particula...

Little America

(Encyclopedia)Little America, base for Antarctic exploring expeditions, Antarctica, on the Ross Ice Shelf, S of the Bay of Whales. Richard E. Byrd, a U.S. explorer, established and named Little America in 1929 and ...

Gerhardt, Charles Frédéric

(Encyclopedia)Gerhardt, Charles Frédéric shärl frādārēkˈ zhārärˈ [key], 1816–56, French chemist, b. Strasbourg. He revived the theory of acid radicals, which he called the theory of residues, and did va...

Pembroke, town, Wales

(Encyclopedia)Pembroke pĕmˈbro͝ok [key], Welsh Penfro, town (1991 pop. 7,049), Pembrokeshire, SW Wales, on an inlet of the Milford Haven estuary. The town is an agricultural market with tourism, ship repairing, ...

threonine

(Encyclopedia)CE5 threonine thrēˈənēn [key], organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essen...

Mitscherlich, Eilhard

(Encyclopedia)Mitscherlich, Eilhard īlˈhärt mĭchˈərlĭkh [key], 1794–1863, German chemist. He was professor at Berlin from 1822. Noted for his discovery of the principle of isomorphism, he did important wor...

boric acid

(Encyclopedia)boric acid, any one of the three chemical compounds, orthoboric (or boracic) acid, metaboric acid, and tetraboric (or pyroboric) acid; the term often refers simply to orthoboric acid. The acids may be...

Willstätter, Richard

(Encyclopedia)Willstätter, Richard rĭkhˈärt vĭlˈshtĕtər [key], 1872–1942, German chemist. He was professor at the Kaiser Wilhelm Institute of Chemistry, Berlin (1912–16), and at the Univ. of Munich (191...

Grassmann, Hermann Günther

(Encyclopedia)Grassmann, Hermann Günther hĕrˈmän günˈtər gräsˈmän [key], 1809–77, German mathematician and Sanskrit scholar, educated in Berlin. He invented a new algebra of vectors (somewhat similar to...