RELATION TO TRANSCENDENTALISTS 131 



sphenoid being a vertebral centrum the fact (established by 

 Kerkring, 1670), that it develops from two centres. 1 



Von Baer's relation to transcendental anatomy was in 

 some ways a close one, though he was a trenchant critic 

 of the extreme views of the school. 2 He took from Oken the 

 idea that a simple fundamental plan rules the organisation 

 of all Vertebrates ; " That jaws and limbs are modifications of 

 one fundamental form is readily apparent, and, after Oken, the 

 fact ought to be accepted by the majority of those naturalists 

 who do not refuse to admit the existence of a general type 

 from which the diversity of structure is developed " (i., p. 192). 

 He accepted the vertebral theory of the skull in its main 

 lines, and used his embryological knowledge to support the 

 idea that jaws correspond to limbs the latter point as part of 

 the transcendental idea that the hind end of the body repeats 

 the organisation of the anterior part (i., p. 192). The 

 particular form which his theory of the relation of jaws 

 to limbs took is shown in the following passage : " The 

 maxillary bone has . . . the significance of an extremity 

 and at the same time that of a rib or lower arch of a 

 vertebra, just as the pelvic bones unite in themselves the 

 signification of ribs and proximal members of the hinder 

 extremity" (Meckel's Arc/iiv, p. 367, 1826). 



He appreciated the morphological idea of the serial 

 repetition of parts, and gave it accurate formulation. The 

 whole vertebrate body, he considered, was composed of 

 a longitudinal series of morphological elements, each of 

 which was made up a section from each of the fundamental 

 organs a vertebra, a section of the nerve-cord, and so on 

 (EutwickelungsgeschicJite, ii., p. 53). Groups of these morpho- 

 logical elements formed morpJiological divisions, such as the 

 vertebral segments of the head with their highly developed 

 neural arches, or the segments of the neck with their un- 

 developed haemal arches. The morphological elements are 

 clearly shown only in the animal parts, but there are indica- 

 tions in the embryo of a segmentation also of the vegetative 

 parts, the gill-slits, for instance, and the vascular arches. 



1 Lemons d? Anatomic comparee, 3rd ed., vol. i., p. 4^4, Bruxelles, 1836. 



2 In the aforementioned paper in Miiller's Archiv he criticises 

 Carus vigorously and is sarcastic on Geoffroy. 



