REGRESSIVE METAMORPHOSIS. 87 



of descendence of one bioplast from another, and the 

 germinal, or developmental faculty, not only survives 

 in the adults of the higher individuals in ordinary 

 nutrition, but " in fully-formed organs there exists a 

 certain proportion of embryonic germinal matter which 

 may undergo development at a future period of life, 

 and if the greater part of this becomes fully-formed 

 tissue, still there remains embryonic matter for de- 

 velopment at a still later period, and so on" ("Croonian 

 Lecture," p. 263). He instances the white corpuscles as 

 examples of undifferentiated protoplasm which are 

 descended from an early embryonic period and have 

 more capacity for differentiation. To these he ascribes 

 the power of forming cuticle and white fibrous tissue 

 in the healing of wounds. 



Beale's theory, in fact, harmonizes with, and realizes, in a 

 more precise form, the theory of epigenesis of Caspar Wolff, 

 who, we are reminded by Huxley and Hackel, is the true 

 founder of the modern theories of development. Like Wolff, 

 Beale traces the evolution of the whole complex organism of 

 plants and animals to the growth, sub-division, and differentia- 

 tion of a little mass of clear, viscous, structureless matter. The 

 developmental history of living organisms is usually spoken of 

 as synonymous with embryology, although that word properly 

 applies only to the organism within the envelopes of the ovum. 

 According to Hackel, the more correct term would be " onto- 

 genesis."* Each individual of the higher orders, in the process 

 of ontogenesis, passes through the lower stages which represent 

 the permanent form of beings of lower orders of individuality. 

 The process of their evolution or development, as a whole, 

 consists therefore of building up, metamorphosis, and re- 

 gression or decay. By many the word evolution is restricted 



* "Gen. Morph.," vol. i. p. 53. 



