NATURAL SELECTIOJS-, ETC. 93 



the human no less than the lower animal races out of 

 some simple primordial animal — that all are equally 

 " lineal descendants of some few beings which lived 

 long before the first bed of the Silurian system w^as 

 deposited." But, as the author speaks disrespectfully 

 of spontaneous generation, and accepts a supernatural 

 beginning of life on earth, in some form or forms of 

 being which included potentially all that have since 

 existed and are yet to be, he is thereby not warranted 

 to extend his inferences beyond the evidence, or the 

 fair probability. There seems as great likelihood that 

 one special origination should be followed by another 

 upon fitting occasion (such as the introduction of man), 

 as that one form should be transmuted into another 

 upon fitting occasion, as, for instance, in the succession 

 of species which differ from each, other only in some 

 details. To compare small things with great in a 

 homely illustration : man alters from time to time his 

 instruments or machines, as new circumstances or con- 

 ditions may require and his wit suggest. Minor altera- 

 tions and improvements he adds to the machine he 

 possesses ; he adapts a new rig or a new rudder to an 

 old boat : this answers to Yay^iation. " Like begets 

 like," being the great rule in l^ature, if boats could 

 engender, the variations would doubtless be propa- 

 gated, like those of domestic cattle. In course of 

 time the old ones would be worn out or wrecked ; the 

 best sorts would be chosen for each particular use, and 

 further improved upon ; and so the primordial boat 

 be developed into the scow, the skiff, the sloop, and 

 other species of water-craft — the very diversification, 

 as well as the successive improvements, entailing the 



