Know Thyself 41 



tentation for bodies; while transformation is a uni- 

 versal law of the origin of bodies. 



(8) The dependence of living beings on chemical 

 substances is only a special case of the general law of 

 transformation and conservation; but the discovery of 

 it merits inclusion in our list of science's prime achieve- 

 ments because of its great importance to the problem 

 of man's dependence upon nature. 



(4) Concerning the origin of individuals and spe- 

 cies, the transformations involved are of two radically 

 different sorts. First, there is the sort known as 

 organic evolution, which does not consist in a literal 

 transformation of parent into offspring, that is, in a 

 changing over of parent into offspring without loss of 

 weight as one physical or chemical body changes into 

 another, but rather in a growth of the derived indi- 

 vidual or species from a small portion of the parent. 

 And second, this growth is accomplished by the trans- 

 formation of foreign substances into the growing 

 organism through the nutritive process. 



( 5 ) The far-reaching facts of what I have called in- 

 dividual specificity among organisms have only lately 

 come clearly to light, and even yet their significance is 

 but vaguely seen. In the middle and later years of last 

 century, biologists talked much about Protoplasm, 

 written with a capital P, the assumption being that 

 there is one simple substance common to all life. But 

 the capital P has gradually disappeared from scientific 

 writing, for we are learning that each species and indi- 



