256 THE CAUSES WHICH 



sive descent by successive modification and consequent acquirement 

 of new powers. Yet it must not be denied this, the theoretical 

 view of the question, since its advocation by Dr. Darwin,* has 

 met with notable opposition from the professional and scientific 

 world. There is the specialist, who on the one hand acknow- 

 ledging a grandeur of conception and limited certain application, 

 yet hesitates in its adoption, from the apparent introduction of 

 typical forms, their persistence, or inverse disintegration, in the 

 geological strata, or from a tendency of varieties to recur ; or, as 

 regards man, from some negation to volition in connection with 

 his progress. There is also the cosmological dogma, which 

 assumes each species of organic life endowed with an invariable 

 structure and properties, adapting it best for the kind of life for 

 which it was designed, but which advances nothing to account 

 for its existence, and a spontaneous evolution theory, which 

 supposes organisms to arise without germs ; laws which, up to 

 the present time, have afforded mankind no evidence of their 

 existence. t On the other hand, the more modern evolution 

 theory finds support in the embryological, which is now very 

 generally accepted among students as harmonising with the 

 geological evidence. 



As regards reproduction, the embryological theory which traces 

 the descent of the organic world in its growth is well known. 

 How the various forms arise in the germ from the uniting and 

 increase by division of organic cells to a frothy structure termed 

 " blastoderm,^' that separates into two or more layers according 

 to the complicity of organisation of the individual, and in which 

 the several parts systematically appear : the spinal cord, observ- 

 able from the Ascidian upwards ; the similar division of : the 

 embryo into segments ; the bars posterior to the mouth, which 

 in fish become gills, but in reptiles, birds, and mammals form 

 very different parts ; or, lastly, the bone, which, suspending the 

 lower jaws of birds and reptiles, is converted in mammals into 



* " Origin of Species," "Descent of Man," and other works. 



f See "Insect Transformations," chap.i., "Lib. of Entertaining Knowledge," 

 Lond., 1830; also "Fragments of Science," by Professor Tyndall, Vol. II., pp. 

 253 — 336. The mooted points are the phenomena of fermentation and putre- 

 faction. As some theologico-physiological difficulty appears to have arisen 

 with regard to the sig-nilication of the word " Bara " [created) in Genesis, the 

 writer may be forgiven if he refers to its use in Ps. civ. 30. 



