Problems, Concepts and Their History 



15 



Oppenheimer, '40), but their views were 

 relatively mild compared to those of many 

 who followed them. The culmination was 

 the work of Haeckel, the greatest revisionist 

 of them all. 



The most extreme example of his immod- 

 eration was perhaps his naming, on the basis 

 of the "similarity, or homology, of the gas- 

 trula in all classes of compoimd animals" 

 (concept originally expressed in monograph 

 on the Kalkschwdmme, 1872; cited here 

 from Haeckel, [1900], p. 61), in the stead of 

 the coelenterates formerly nominated for the 

 position by Kleinenberg, the imaginary gas- 

 traea as the progenitor of all multicellular 

 forms. His figuring of a section through an 

 animal that never existed on the same page 

 (1891, p. 161) that illustrates Kowalewski's 

 gastrulae of Sagitta and Amphioxus and Carl 

 Rabl's of Limnaeus, with no comment in the 

 label to signify that the "Gastrula eines 

 einfachsten Pflanzenthieres, einer Gastraeade 

 (Gastrophysema, Haeckel)" is any less real 

 than the others — where is there a handsomer 

 example in all biological or scientific his- 

 tory of what Whitehead has called the 

 "Fallacy of Misplaced Concreteness"? 



Such a silly invention as the gastraea, 

 that "magere Tiergespenst," as Kleinenberg 

 (1886, p. 2) called it, as an isolated case 

 might probably have proved of little influ- 

 ence; and its significance is as a symptom (a 

 word used advisedly for its pathological con- 

 notations) of Haeckel's basic trouble. What 

 was damaging to science was Haeckel's fer- 

 vency to oversystematize all morphology 

 through his biogenetic law that "die Onto- 

 genie ist eine Recapitulation der Phylogenie" 

 (1891, p. 7). _ 



In formulating it, he returned to the law 

 of parallelism of Tiedemann, Meckel and 

 Serres, quite by-passing von Baer's more 

 temperate statements. He was influenced to 

 do so of course in part by Fritz MiAller, who 

 had earlier (Fiir Darwin, 1864) pointed out 

 on the basis of the study of crustacean 

 larvae that individual development provides 

 a clue to ancestral history. But he misinter- 

 preted Miiller, as have many more modern 

 readers (cf. Meyer, '35). While Miiller was 

 supporting Darwin — indeed, as Meyer says 

 ('35, p. 392), "his main conclusion was that 

 his studies on the development of Crustacea 

 confirmed Darwin's idea of evolution" — he 

 yet was formidating no such dogma as 

 Haeckel's concerning the causal relation- 

 ships between evolution and individual de- 

 velopment. 



Sir John Lubbock, too, was early consider- 



ing the relationships of evolution and indi- 

 vidual development in support of Darwin; 

 but when he questioned whether insects dur- 

 ing the course of metamorphosis pass through 

 their ancestral stages he felt forced to a 

 negative reply in the absence of evidence 

 that a caterpillar ever existed as a fully de- 

 veloped organism. Radl has commented ('30, 

 p. 140) concerning the biogenetic law that 

 "everything important that has ever been 

 cited against the theory was known when 

 the theory was first put forward; neverthe- 

 less it was widely accepted." Lubbock's res- 

 ervation is an example. But his exception, 

 and all the other exceptions, seemed to lack 

 the dramatic appeal of the false generaliza- 

 tion, and the biogenetic law was acclaimed 

 with the same rapt enthusiasm that had 

 greeted the earlier theories of preformation 

 and of unity of type. 



Investigators in widely varied fields of 

 interest rapidly carried over the theory into 

 their own territories. Bunge applied it to 

 physiology: 



The amount of common salt in the organism cor- 

 responds with the amount in the environment. . . . 

 Many plants contain only traces of sodium; those 

 which are rich in it are only the sea-weeds and the 

 plants which grow on the sea-shore, and on the 

 salt-steppes which are dried-up sea-basins. . . . 



This is also the case with invertebrate animals; 

 only those which live in the sea, and those nearest 

 allied to them on land, contain much salt. . . . 



The land vertebrates are all remarkably rich in 

 salt, in spite of the scanty supply around them. But 

 even these are only apparent exceptions. We need 

 but remember the fact that the first vertebrates on 

 our planet all lived in the sea. Is not the large 

 amount of chlorid of sodium found in the present 

 inhabitants of dry land another proof of the gene- 

 alogical connection we are forced to accept from 

 morphological facts? . . . 



If this interpretation is correct, we should expect 

 that the younger the vertebrates are in their in- 

 dividual development, the more salt they would 

 possess. This is in fact the case. I have convinced 

 myself by numerous experiments that an embryo of 

 a mammal contains more salt than a new-born 

 animal, and that it gradually becomes, after birth, 

 poorer in chlorin and sodium as it develops. Cartil- 

 age contains the most sodium of any tissue in our 

 bodies, besides being also the tissue of greatest an- 

 tiquity. . . . This phenomenon . . . can only be 

 explained by the theory of evolution" ('02, pp. 101- 

 103). 



Workers in other fields than biology, too, 

 adopted the theory with as much warmth. 

 Preyer, a colleague of Haeckel's at Jena, for- 

 mulated his conceptions of child psychology 

 with reference to Haeckel's law; Herbarl 

 and Ziller before him had held that the in- 



