LAW OF REPETITION 95 



sternum is a ventral vertebral column. Limbs are connate 

 ribs, the digits indicating the number of ribs included (cf. 

 Duges, supra.) p. 88). 



J. F. Meckel 1 discusses " homologies " of this kind in the 

 thorough and pedestrian way so characteristic of him. Not 

 only, he says, are the right and left halves of the body 

 comparable with one another, but also the upper and the 

 lower, the dividing line being drawn at the level of the 

 diaphragm. The lumbar complex corresponds to the skull, 

 the anus to the mouth, the urino-genital opening to the 

 nasal opening ; in general, the urino-genital system corre- 

 sponds to the respiratory, the kidneys to the lungs, the 

 ureters to bronchi, the testes and ovaries to the thymus (he 

 had observed the physiological relation between the develop- 

 ment of the thymus and the state of the genital organs), the 

 prostate and the uterus to the thyroid gland, and the penis 

 and clitoris to the tongue. The fore - limbs and girdle 

 correspond in detail with the hind limbs and the pelvis 

 a point already worked out by Vicq d' Azyr ; the dorsal and 

 ventral halves of the body are likewise comparable in some 

 respects, the sternum, for example, answering in the arrange- 

 ment of its bones, muscles and arteries to the vertebral 

 column. The skeleton of each member is in some respects 

 a repetition of the vertebral column. 



His brother, D. A. Meckel, 2 worked out an elaborate 

 comparison between the alimentary canal and the genital 

 organs, basing the legitimacy of the comparison upon early 

 embryological relations and upon the state of things in 

 Ccelentera, where genital and' digestive organs occupy the 

 same cavity. In his view the uterus corresponded to the 

 stomach, the vagina to the oesophagus, the fallopian tubes to 

 the intestine, and so on. 



The vertebral theory of the skull took its origin from the 

 same habit of thought. As part of the wider idea of the 

 metameric repetition of parts it had some scientific worth, 

 but the theory was pushed too far, and the facts were twisted 

 to suit it. Among annulate animals the theory of repetition 

 found ample scope; Oken was able to compare with justice 



1 Beytriige, ii., 2, 1812. Also in his System d. vergl. Anat.^ i., 1821. 



2 In J. F. Meckel's Beytrdge, ii. 



