250 THE HISTOilY OF CREATION. 



There appears indeed to be a limit given to the adapt- 

 ability of every organism, by the " type " of its tribe or 

 phylum ; that is, by the essential fundamental qualities 

 of this tribe, which have been inherited from a common 

 ancestor, and transmitted by conservative inheritance to all 

 its descendants. Thus, for example, no vertebrate animal 

 can acquire the ventral nerve-chord of articulate animals, 

 instead of the characteristic spinal marrow of the vertebrate 

 animals. However, within this hereditary primary form, 

 within this inalienable type, the degree of adaptability is 

 unlimited. The elasticity and fluidity of the organic 

 form manifests itself, within the type, freely in all directions, 

 and to an unlimited extent. But there are some animals, 

 as, for example, the parasitically degenerate crabs and 

 worms, which seem to pass even the limit of type, and 

 have forfeited all the essential characteristics of their tribe 

 by an astonishing degree of degeneration. As to the 

 adaptability of man, it is, as in all other animals, also un- 

 limited, and since it is manifested in him above all other 

 animals, in the modifications of the brain, there can be 

 absolutely no limit to the knowledge which man in a 

 further progress of mental cultivation may not be able to 

 exceed The human mind, according to the law of unlimited 

 adaptation, enjoys an infinite perspective of becoming ever 

 more and more perfect. 



These remarks are sufiicient to show the extent of the 

 phenomena of Adaptation, and the gTeat importance to 

 be attached to them. The laws of Adaptation, or the 

 facts of Variation caused by the influence of external con- 

 ditions, are just as important as the laws of Inheritance. 

 All phenomena of Adaptation, in the end, can be traced to 



