SKELETON. 



637 



yields the mammal spine as it is, normally or 

 abnormally. 



PROP. XXVII. The numerical length of the 

 lumbar spinal region depends upon the num- 

 ber of archetypes subjected to metamorphosis. 

 The first lumbar vertebra, that which 

 succeeds 19, b, fig. 458., counts twentieth 

 from the occiput, and thirteenth after the 

 last cervical vertebra, when this latter counts 

 seventh from the occiput ; and it is ac- 

 cording to the character of the costal ap- 

 pendages of this first lumbar segment of the 

 spinal series, that we are inclined to regard it 

 as belonging to the category of thoracic or of 

 lumbar spinal segments. When it produces 

 articular costae, it stands in true thoracic 

 character, and adds to the number of thoracic 

 segments, at the same time that it subtracts 

 from the number of lumbar vertebrae. In 

 this respect, namely, that of influencing the 

 numerical series of the spinal regions ac- 

 cording as the ribs are standing plus upon it 

 or otherwise, this first lumbar vertebra is 

 similar to the seventh cervical vertebra. As 

 the numerical length of the cervix depends 

 upon the presence or absence of cervical ribs, 

 produced from the seventh cervical vertebra, 

 and as this very condition influences also the 

 length of the thoracic series, so does the 

 numerical length of the lumbar region de- 

 pend upon the presence of lumbar ribs pro- 

 duced in plus or minus dimensions from the 

 first lumbar vertebra ; and this is the very 

 fact which also influences the length of the 

 thoracic series. The inference to be drawn 

 from these facts is obvious enough. The 

 abnormal as well as the normal conditions of 

 the lumbar spine, in regard to the ribs, prove 

 that lumbar vertebra?, as well as cervical ver- 

 tebrae, are proportional figures degraded from 

 the costo-vertebral thoracic archetype quan- 

 tities such as I have drawn them in fig- 455., 

 from 1 to 24. 



PROP. XXVIII. The numerical length of 

 the sacral and coccygeal series is not fixed, and 

 this is owing to the same fact of archeti/pes un- 

 dergoing metamorphosis. Though the human 

 anatomist speaks of a spinal figure under the 

 name of first sacral and first coccygeal vertebra, 

 it is not hence to be inferred that this form pre- 

 sents, in all human spinal axes of a fixed and 

 invariable character, either as to osseous quan- 

 tity or numerical position. In order to prove 

 that such is the changeable character of the 

 form named sacral and coccygeal vertebras, 

 we have only to fix attention upon its nume- 

 rical situation in several spinal axes of even 

 human species ; and we shall find that the 

 first sacral vertebra of one spine is the last 

 lumbar vertebra of another spine. In like 

 manner we shall see that the first coccygeal 



the idea I wish to create as contradistinguished from 

 the ideas promulgated in " The Homologies of the 

 Vertebrated Skeleton," where I find that the author, 

 in his figures of the archetype of mammalian, avian, 

 and reptilian forms, leaves their cervical regions 

 standing in their class proportions, as though tla^r 

 were "archetypal," " the general," " the fundamental 

 type." 



vertebra of one spine is the fifth sacral of 

 another spine. In the " normal " condition 

 of the human spine, the first sacral vertebra 

 (fig. 455./) counts as the twenty-fifth reckon- 

 ing from the occiput ; but if we will compare 

 and examine a large number of human ske- 

 letal axes, we shall see that the twenty-fifth 

 spinal segment or vertebra is not always 

 standing in sacral condition. I have found 

 that this twenty-fifth spinal vertebra is some- 

 times in lumbar and sometimes in sacral 

 form, a circumstance which proves that 

 sacral character is mainly owing to the juxta- 

 position of the iliac bones. Upon which- 

 ever vertebra of the lumbar spine, whether 

 it be f, or the one before or behind f, Jig. 

 455., the iliac bones abut, this determines its 

 sacral character. This sacro-iiiac junction 

 does not always occur between the twentv- 

 fifth vertebra of the human spinal series and 

 the iliac bone. 1 have occasionally seen it at 

 the twenty-fourth and at the twenty-sixth 

 numerical vertebra of spinal series. When 

 the sacro-iliac junction happens between the 

 twenty-fourth vertebra and the iliac bone, the 

 human lumbar spine reckons only four ver- 

 tebrae, provided the last thoracic be the 

 nineteenth. When, again, this junction takes 

 place between the twenty-sixth vertebra and 

 the iliac bone, then the lumbar spine reckons 

 six vertebrae provided always the last thoracic 

 costo-vertebral segment be the nineteenth. 

 These variations in the numerical length of 

 the lumbar spine, occur according to the 

 spinal position of the iliac spinal junction ; 

 and it will hence appear that the sacro-coccy- 

 geal series of spinal forms must also be in- 

 fluenced by the same facts. 



PROP. XXIX. A comparison of the same 

 numerical vertebra in all human spinal axes 

 will prove the truth of the present interpre- 

 tation of the law which governs the develop- 

 ment of all vertebral forms, not only in the 

 same spine, but all other spines. When I 

 say that the seventh cervical vertebra of 

 figA55. is a proportional metamorphosed from 

 its own costo-vertebral archetype or whole 

 quantity, and which archetype is the equal 

 of that which stands as the first thoracic 

 costo-vertebral form, viz. that marked 8 in 

 Jig. 455., have I not a certain proof of the truth 

 of this interpretation, when upon comparing 

 this seventh cervical vertebra of fig. 455. with 

 the seventh cervical vertebra of v,fig. 457., or 

 that of fig. 458., I find that the very same 

 numerical seventh cervical vertebra is, in the 

 one skeleton (fig. 455.), of cervical, and in 

 the other skeleton (fig. 458.), of thoracic cha- 

 racter. For it is the presence or persist- 

 ence of the cervical ribs which determines its 

 character in this case as thoracic, and it is 

 the absence or rudimentary condition of the 

 ribs which in the other case stamps it as cer- 

 vical. Again, when I say that the twentieth 

 spinal vertebra of fig.455., reckoning after the 

 occiput, and which twentieth vertebra is the 

 first lumbar vertebra, must be considered as a 

 proportional or lesser form metamorphosed 

 from such another whole archetype as the 



