CHAP, xv.] THE PEDIGREE AND OrJGIN OF THE CAT. 



523 



always miuute chani^cs. If, however, a sudden and considerable 

 change took place, this difficulty, in the way of evolution, would be 

 completely evaded. But what is here said of MacJmrodus, has a 

 wide application. Were not forms of life evolved by a process which, 

 compared with their duration, is "sudden," the world would be a 

 zoological chaos. But such is not the case. A multitude of un- 

 doubtedly stable and plainly distinct kinds exist now, and thence 

 we may conclude that stable and distinct kinds always existed, how- 

 ever difficult the definition of some forms may be in certain cases. 



Eeturning from this digression to the question as to the mode of 

 individual development and evolution, if we extend our view beyond 

 the class of mammals, far more striking phenomena will present 

 themselves to our notice than any with which we have become 

 acquainted in studying the development of the cat. Thus in the 

 development of such an animal as the frog, we find that two 

 remarkable transformations take place. One of these is the trans- 

 formation of the egg into a fish-like tadpole, the other is the 

 transformation of the tadpole into the frog. In that singular species 

 of Mexican eft, the axolotl, we find that a few individuals will every 

 now and then (under the stimulus of certain conditions of their 

 environment) quickly undergo a transformation, not merely of 

 external appearance, but one which affects their very skeleton, and 

 changes the distribution of the teeth in their jaws. In insects, as 

 c.(j., in the butterfly, we have the well-known marvellous meta- 

 morphosis which is efiectcd during the period of its existence as a 

 quiescent chrysalis. Other lowly animals undergo still more sur- 

 prising changes^ which in many of them, as in the Tunicates, may 

 result in the production of an adult form which is of a loiccr order of 

 organization than that of the transient being which served to evolve 

 it. Such facts as these show how probable it is, that at various 

 different stages of individual evolution, sudden changes caused by an 

 acceleration or by an arrest of the development process, or even by 

 some retrogressive action, may have resulted not merely in the 

 production in the concrete of new species, but even of a new genus, 

 a new family, or a new order ; for we see equivalent changes going 

 on before our eyes now.* 



. . . Such appears to be constantly tlie 

 fate of forms whicli have become over- 

 specialized, or in -which the development 

 of one part has run ou in one particular 

 direction out of due proportion to the 

 rest of the organization. We know that 

 it is quite possible, by artificial selection, 

 to produce animals with one particular 

 part developed even detrimentally to the 

 entire economy of the creature, and it 

 really seems as if something of the same 

 kind not unfreipiently occurs in nature." 

 It is indf^d true that for the perfection 

 of any living creature there is need of 

 harmony between its various powers, 

 and a moral may be drawn fiom the 



above instance as to the dangers likely 

 to result to any race of mankind from a 

 one-sided, ill-balanced development of 

 those intellectual powers which give man 

 supremacy over all lower forms of life. 



* Some readers may feel a difficulty in 

 accepting the view here put forward (as 

 to the serial succession of different 

 psychical principles of individuation in 

 the development of each individual 

 animal such as the cat, frog, or butterfly), 

 on account of the gradual mode in which 

 even rapid metamorphoses take place. 



The tadpole onl}^ by degrees becomes a 

 frog, and gradual processes of change 

 take place within the seemingly (j^uies- 



