TYPES OF CONSTRUCTION. 73 



gradations in nature as some imaginations have conceived. 

 There are so many relationships, both of structure and 

 of function, that a single series is out of the question. 

 There are many series, and series, also, within series. 

 Organic forms seem to be placed in radiating groups 

 rather than lines, each group being connected, not with 

 two groups merely, one above and the other below, but 

 with several. Living things are, therefore, best studied 

 in groups, or circles, according to prominent types or 

 representative forms. These groups will, doubtless, be 

 unequal and dissimilar, and will be far from representing 

 the grade of organization ; yet they will be of great use, 

 not only to the memory, but also in indicating the gen- 

 eral order of the universe. 



3. The unity of organic nature is seen in the similarity 

 of bioplasm, or living matter ; its variety is shown in the 

 multiform arrangements of structure in living beings. 

 That all this variety can be intelligently connected to- 

 gether in a few comprehensive groups, exhibiting plans 

 of structure, is proof positive of the intelligence of the 

 creative power. Agassiz has well said, " If these classi- 

 fications are not mere inventions, if they are not an at- 

 tempt, to classify for our own convenience the objects we 

 study, then they are thoughts which, whether we detect 

 them or not, are expressed in Nature then Nature is 

 the work of thought, the production of intelligence, car- 

 ried out according to plan, therefore premeditated and 

 in our study of natural objects we are approaching the 

 thoughts of a Creator, reading his conceptions, interpret- 

 ing a system that is his and not ours." 



4. Types are comprehensrve natural groups of living 



