CHAPTER XL 



ORGANIC DEVELOPMENT. 



IT has been stated in the last chapter that life exists prior 

 to organization, and is the cause of organization. The 

 germs out of which all organisms are developed are with- 

 out organization or structure ; and the process of organic Develop- 

 development consists in the transformation of structureless ™™V'tli" 

 " germinal matter " into the characteristic structure of the acquisition 

 species to which it belongs. This process is essentially the ture by'a 

 same, whether the germ is nourished within the egg or structure- 



less ffenu 



within the body of the mother until its development is far 

 advanced, as occurs among the higher animals, or whether 

 it is cast loose while it is yet almost without structure or 

 organization, as occurs among the lower ones. 



Structure is defined as the constitution of the separate 

 tissues of an organism (as, for instance, bone, muscle, 

 nerve, leaves, or wood) ; organization is the relation of Histology 

 these to each other. The science of structure is called ^® ^^^ f 

 Histology ; that of organization, in this more limited sense, tissues ; 

 is called Anatomy. l^^^ll 



Normally, development is from the germ, or embryo, to Repair of 

 the perfect form. But the process is essentially the same ^"J""^^/' 



'' C<IS6 01 Q,e~ 



when a lost part is re-formed. All animals possess some- velopinent 

 thing of this power : the newt will reproduce a lost leg, or 

 even a lost eye ; and there have been remarkable instances 

 of similar powers in man, though ia most cases it does not 

 go farther than the healing of wounds.^ When develop- 

 ment goes on normally, from the germ to the matui-e form, 

 it is effected by the gradual transformation of the formless 



1 Carpenter's Human Physiology, p. 355. 



