632 



SKELETON. 



and sternum drawn at neck and loins, as well neck and loins, than to understand her as 



as thorax, degrades this prime-model to the having first given creation to an ens of 



dimensions of a specific or proportional lesser proportions (such as fig. 455.), with 



variety, by obliterating costal quantity at the cervical and lumbar vertebrae lesser than 



Fig. 455. 



TJie Mammalian Skeletal A.xisj 



Showing in dotted outline at the neck and loins those costo-sternal quantities which, if present, 

 would render these regions equal to, and uniform with, the thorax. 



those of the thorax, and then varied all 

 other forms to this ens by a superaddition of 

 new and hitherto unknown elements. The 

 former idea is that which I am endea- 

 vouring to establish throughout these pro- 

 positions. Original uniformity, or the prime 

 model or archetype, viz. Jig. 455., with the 

 costo-sternal quantities at neck and loins, 

 is that figure whose proportions I mean to 

 develop by my mode of comparison ; and 

 the idea that the degradation or subtraction 

 of parts proper to this archetype is that law 

 which becomes the creator of specific variety. 

 When I find that the osseous quantity of a 

 caudal centrum, a sacral, a lumbar, or a 

 cervical vertebral quantity can severally be 

 referred to the like quantities contained in a 

 sternal thoracic costo-vertebral segment*, I 

 entertain the opinion that the latter, as a 

 whole or prime model, has undergone meta- 

 morphosis to the creation of such propor- 

 tional variety as the former instance : and 

 this opinion, I fancy, is more consonant with 

 reason, or is, at least, more pliable for un- 

 derstanding, than to suppose that nature, 

 after having first given creation to the caudal, 

 lumbar, or cervical segments of the spinal 

 axis, created, as it were by after thought, 

 other figures secondary and special to such as 



* Every lesser unit of the vertebral chain finds 

 its quantitative homologue in a part of the greater 

 unit, and all lesser units in the greatest unit, which 

 I therefore name as the archetype. In the following 

 beautiful sentence, Carus expresses his idea of the 

 organic whole quantity compared with the lesser 

 thing or species : " La partie d'un tout organique 

 est incontestablement douee d'un organisation d'au- 

 tant plus elevee qu'elle repete plus parfaitement en 

 elle Pide'e du tout, et le tout lui-meme est d'autant 

 plus parfait qu'ii correspond d'avantage a 1'idee de 

 la nature entiere dont nous devons reconnaitre que 

 1'essence est Punite des lois e'ternelles revele'es dans 

 Pinfinie diversite' de la manifestation." See C. G. 

 Carus,Traite' Element, d' Anatomic Comp. c. xi. p. 26., 

 traduit par J. L. Jourdan ; see also Carus, Von den 

 Urtheilen des Knocheu und Schalengerustes, fol. 

 Leipzic, 1828. 



these by the addition of new and unknown 

 elemental structure, such as a thoracic rib 

 and a sternal piece ; for in the absence or 

 presence of certain elements consists all 

 the specific difference between all segments 

 and regions of the mammalian spinal axis. 



PROP. XVII. Uniformity of structure is a 

 condition proper to the plus thoracic origi- 

 nals of the spinal axis of the mammalian body. 

 It is a demonstrable fact, that all the spinal 

 segments of those regions (fig. 455.), named 

 cervical, lumbar, and sacral, differ from the 

 first seven thoracic costo-vertebral circles 

 (those numbered from 8 to 14) by quantity 

 only ; and this quantity is costo-sternal. It is 

 also demonstrable, that the coccygeal seg- 

 ments of the spinal region, represented by the 

 centrum (5, fig. 453.), differ from the same 

 whole forms by quantity only : this quantity 

 is the neural arch and spinous process, in 

 addition to costo-sternal elements, all of 

 which I have drawn in dotted outline around 

 the caudal centrum (5,.;?g. 453.). Now this 

 differential condition, visible between all such 

 spinal segments, being one of quantity only, 

 it must appear evident that the idea of a 

 structural uniformity can alone be established, 

 first by interpreting the present condition of 

 cervical, lumbar, sacral, and caudal segments, 

 as being one of proportional variety ; and 

 second, by comparing them as such with their 

 originals, which I assert to be of sternal costo- 

 vertebral quantity. If, then, the original or 

 archetypal quantity of a caudal, a sacral, a 

 lumbar, or a cervical segment be a sternal 

 costo-vertebral segment, it will follow that 

 the series of such originals constitutes plus 

 uniformity, as indicated in fig. 455., whose 

 serial units at neck and loins are equated with 

 the thoracic units, whereas the series of such 

 segments as cervical, lumbar, sacral, and 

 caudal quantity constitutes proportional va- 

 riety or specific difference, created out of the 

 substance of the uniform archetype costo- 

 vertebral originals. In order to fix the idea 



