332 THE MECHANICAL FUNCTIONS. 



various parts are to be adapted. Yet, amidst all these varia- 

 tions, we may perceive the same laws of analogy connecting 

 the whole into one series, and assimilating all these multi- 

 form structures to one common standard. The same organ, 

 however modified in its shape and size, however stinted in 

 one, or developed in another, is ever found in its appropriate 

 place, and retains the same connexions with adjacent organs, 

 whether we seek, it in the carnivorous or the herbivorous 

 quadruped, in the inhabitant of the land or of the water, in 

 the denizen of the frigid or of the torrid zone; or in animals 

 of the most diminutive or most colossal statures. 



As an example, we may take the vertebrae of the neck. 

 It is a universal law, that this part of the spinal column 

 shall, in every animal of the class mammalia, consist of 

 neither more nor less than seven vertebrae. Whatever be 

 the length or shortness of the neck, whether it be compressed 

 into a small space, as in the elephant and the mole, whether 

 it be lengthened to allow the head to reach the ground, as 

 in the horse and the ox, or whether it be excessively pro- 

 longed to allow the animal to reach the tops of the trees, as 

 in the cameleopard, still this same constant number is pre- 

 served in the vertebrae which it contains. When the neck 

 is long, each individual vertebra must necessarily be length- 

 ened in the same proportion. Thus, in the Cameleopard, 

 the vertebrae of the neck consist of seven very long tubes, 

 joined together endwise, w^ith scarcely any development of 

 spinous processes, lest they should impede the bending of 

 the neck. The greatest contrast to this structure is met 

 with in the Dolphin, and other Cetacea, which present ex- 

 ternally no appearance whatever of a neck, but whose skeleton 

 exhibits cervical vertebrae, closely compressed together, and 

 exceedingly thin, and most of them united together;* every 

 bone, thus formed, however, retains the marks of having 

 originally consisted of separate vertebrae; and still, in this 



* In the cachalot, the whole of these seven vertebrae are usually anchy- 

 losed into one bone. 



