DEGENERATION 



DEGREE 



Degeneration* a biological term used to de- 

 scribe those not unfrequent cases where an entire 

 organism falls below the structural level of its 

 youn<j stages, or where an organ in the same way 

 loses its fullness of function, and becomes more or 

 less atrophied, abortive, and simplified. Thus many 

 parasitic worms, crustaceans, &c. are emphatically 

 simpler than their free-swimming larvae, and the 

 sessile adult Ascidian shows only traces of the 

 vertebrate characters which are plain enough in 

 the active young. Thus, too, a crustacean which 

 starts with a well-developed eye, may exhibit 

 the gradual loss of this on assuming a dark 

 habitat. The term is best confined to cases 

 where a level of structure exhibited during 

 early life is more or less lost in the adult. 

 Degeneration must be distinguished (a) from 

 occasional abortion, ( b ) from Reversion ( q. v. ) to 

 an ancestral type, and (c) from the occurrence of 

 rudimentary and undeveloped organs where a 

 character possessed by ancestral types remains 

 more or less undeveloped, or shows itself only in 

 embryonic life. Degeneration may be due to the 

 environment, or to cessation of function, or to some 

 more subtle constitutional cause. Absence of food, 

 heat, light, &c. may mean the absence of the 

 necessary stimulus for the growth and maintenance 

 of the organs, or superfluity of food may cause one 

 system to preponderate over others. Nor can it be 

 doubted that cessation of function checks the food- 

 supply to a given organ, and in other ways helps to 

 bring about its degeneration. But on the other 

 hand, some less obvious cause the fatigue of early 

 life, a constitutional sluggishness, &c. may share in 

 conditioning degeneration, as in the case of the 

 majority of the Tunicata. Weismann and others, 

 however, would explain degeneration by what they 

 call the non-operation of natural selection. On 

 this view, organs are not only developed but main- 

 tained by natural selection, and if it happen that 

 an organ is no longer an advantage in this struggle 

 for existence (e.g. eyes in dark caves), then natural 

 selection no longer maintains that organ, and it 

 disappears in the course of generations. Weismann 

 applies this ultra-Darwinian conception especially 

 to cases which might be called non-development 

 rather than actual degeneration e.g. to the 

 slightly developed wings of the Apteryx. Most 

 cases of degeneration properly so called appear 

 hardly to require his subtle explanation, but find 

 a sufficient one in the nature of the environment, 

 in the effects of stopped function, and in the 

 constitution of the organism. The theory of the 

 degeneration of man from a high state (see ADAM, 

 FALL) has been superseded by the belief in a 

 development from low savagery (see ANTHRO- 

 POLOGY, ARCHEOLOGY). 



See Ray Lankester, Degeneration (1880); and "Weis- 

 mann, Ueber den Riickschritt in der Natur ( 1887 ). Max 

 Nordau, Degeneration (trans. 1895). See also, for 

 instances, ASCIDIANS, CAVE-ANIMALS, CRUSTACEA, IN- 

 BKCTS, PARASITISM ; also ENVIRONMENT, EVOLUTION, &c. 



De Gerando, JOSEPH MARIE, BARON, was 

 born 29th February 1772, at Lyons, of Italian 

 blood. Fleeing from Paris to Germany, he entered 

 (1797) Massena's army as a private, and wrote a 

 treatise, 'crowned' by the Academy, Des Signesetde 

 VArt de Penser ( 1800). In 1802 appeared his De la 

 Generation des Connaissances Humaines, a precursor 

 of his Histoire de Philosophic (1803), long reputed 

 the best French work on the subject. It procured 

 him, in the following year, admission into the 

 Academy. He was appointed secretary-general to 

 the Ministry of the Interior by Napoleon. But 

 De Gerando is even better known by his philan- 

 thropic writings. His excellent work, Le Visiteur 

 du Pauvre (1820), obtained the Montyon prize, as 

 did also his Du Perfectionnement Moral (1824). 



De Gerando was elevated to the peerage in 1837, 

 and died 12th November 1842, vice-president of the 

 Council of State. 



Deggendorf, a town of Lower Bavaria, on 

 the Danube, which is here crossed by two bridges, 

 39 miles NW. of Passau bv rail, with manufac- 

 tures of paper, linen, woollens, stoneware, and 

 matches. Its church of the Holy Sepulchre is often 

 visited by more than 30,000 pilgrims annually. 

 Pop. 6446. 



Degraded, in Heraldry, means placed upon 

 steps or degrees. 



Degree, the 360th part of the circumference of 

 a circle ; see CIRCLE, GRADUATION. A degree of 

 latitude is the length along a Meridian (q.v. ), such 

 that the difference of latitude between its north 

 and south ends is one degree i.e. from the two 

 positions the altitude of the same star is seen to 

 differ by one degree (see LATITUDE). Another 

 definition is that two points on the earth's surface 

 differ in latitude by one degree, when the verti- 

 cals at these points make angles with the plane 

 of the equator, differing by one degree. Were 

 the earth perfectly spherical in shape, this dis- 

 tance along a meridian would be exactly equal 

 to THHT of the whole meridian, and would be the 

 same at all parts of the earth's surface. But owing 

 to its oblately spheroidal shape it increases from 

 the equator, where the curvature is greater, to the 

 poles, where it is less curved. From geodetical 

 measurements made, it is found that at the equator 

 the length of a degree of latitude is 362746 '4 feet ; 

 while at the poles it is 366479 '8 feet. The differ- 

 ences between the length of the degree of latitude 

 in different latitudes, thus ascertained by actual 

 measurement, is one of the proofs that the figure of 

 the earth is not that of a sphere but that of an 

 oblate ellipsoid. 



A degree of longitude is the length between 

 two meridians that make an angle of one degree at 

 the poles, measured by the arc of a circle parallel 

 to the equator passing between them. It is clear 

 that this space is greatest at the equator, and 

 vanishes at the poles ; and it can be shown that it 

 varies with the cosine of the angle of latitude. The 

 annexed table shows the lengths of a degree of 

 longitude for places at every degree of latitude from 

 to 90. It is computed on the supposition that 

 the earth is a sphere. 



