40 SCIENTIFIC ILLUSTRATIONS [Cha 



serves its vitality, for neither the form nor the colour of its 

 discs is altered ; but the blood is really dead, because its rest- 

 less changes are arrested. Ever wonderful is the fact con- 

 stantly obtruding itself upon us, that life is inseparably linked 

 with change, and that every arrest is death. Only through 

 incessant destruction and reconstruction can vital phenomena 

 emerge, an ebb and flow of being. The moment we preserve 

 organic matter from destruction, we have rendered it incapable 

 of the restless strivings of life. A spirit like that of Faust 

 seems ranging through all matter; and if ever it should say 

 to the passing moment, " Stay ! thou art fair," its career will 

 be at an end. PH. 



Superficial Change without Radical Alteration. 



The Indians of South America have a curious art by which 

 they change the colours of the feathers of many birds. They 

 pluck out those from the part which they wish to paint, and 

 inoculate the fresh wound with the milky secretion from the 

 skin of a small toad. The feathers grow of a brilliant yellow 

 colour, and on being plucked out, it is said, grow again of the 

 same colour without any fresh operation. Here we have an 

 illustration of an attractive change which is merely of a super- 

 ficial character. Of course the birds which are operated upon 

 in this way remain quite unaltered in habits and disposition ; 

 and any person who judges of the nature of the bird by its 

 colours is utterly deceived. One of the triumphs of civilisation 

 consists in decking out men and women so as to improve their 

 external appearance as much as these Indians improve that of 

 the birds. One of our greatest follies consists in being taken 

 in by the imposture. Decorations, and stylish behaviour, no 

 more alter the character of men and women than the milky 

 secretion of the toad alters the character of the birds. Do not 

 judge the habits of the birds by coloured feathers. Do not 

 accept human beings as worthy your confidence merely because 

 their aspect is attractive. They may be detestable persons in 

 nature, and the appearance which has pleased you may be 

 merely the superficial attraction with which the tricks of art 

 have endowed them. TR, 



