5o6 THE HISTORY OF BIOLOGY 



and that, too, in many different spheres — as Haeckel. He has been much 

 disputed — now praised to the skies, now vilely abused. As a matter of fact, 

 it is not at all easy to grasp the true value of his life's work. No important 

 scientific discovery attaches to his name, and the ideas he promulgated are 

 largely borrowed from others. The works that once brought him fame are 

 now hopelessly out of date, but it must be admitted that much in them has 

 now been incorporated in our general knowledge. The idea of evolution, in 

 the form given to it by Darwin, found in Haeckel its most devoted cham- 

 pion; his personality and his trend of thought have set their mark on the 

 elaboration of this theory, especially on the continent of Europe, and they 

 are therefore worthy of closer examination. 



Light is thrown on Haeckel 's early development by two collections of 

 letters, which have since been published, the one addressed to his parents 

 in his student days at Wiirzburg, the other to his betrothed during his Ital- 

 ian journey. This development is highly characteristic of the generation to 

 which he belonged and therefore explains in some degree how it was that 

 he acquired such an influence over his age. Young Haeckel at Wiirzburg 

 is by no means a German "corps" student of the ordinary type; on the 

 contrary, he was a very nice youth, abhorring duels and drinking-bouts, 

 diligently attending lectures and exercises, writing tender and affectionate 

 letters to his parents, regularly attending church, and comforting his lonely 

 hours with pious thoughts. True, he could cause his parents anxiety on ac- 

 count of his dislike for medicine and his propensity for unpractical dreaming, 

 but, on the other hand, he was always ready, with a somewhat rhetorical 

 and precocious eloquence, to confess his weaknesses to his old parents and 

 to promise to make them happy in the future. The most striking feature of 

 these letters is their Christian piety, which contrasts strongly with the 

 hatred that Haeckel felt for Christianity in later years; the youth expresses 

 his indignation against Karl Vogt and other "materialists" of the time in 

 terms that were afterwards used almost word for word against himself. It 

 is, of course, the opinions held in his parents' home that here recur — the 

 old-fashioned, serious, moral-religious atmosphere pervading the home of 

 a Prussian Civil Servant, with its literary and patriotic traditions. At Wiirz- 

 burg young Haeckel was enraged at the Catholic propaganda, which was 

 carried on at that time, during the period of reaction after 1848, with extreme 

 ruthlessness, and at the same time as his father was deploring the unhappy 

 political situation. In the letters from Italy the whole aspect is altered; that 

 was in 1859, ^^^ Y^^^ ^^ ^^^ liberation of Italy. Haeckel is full of enthusiasm 

 over Germany's unification and raves against her opponents, vassal princes 

 and Prussian junkers, who were serving the reactionary politics of Austria. 

 His religious attitude is now something quite different; Christianity has been 

 superseded by a worship of humanity in general, combined with enthusiasm 



