EVOLUTION OF ANIMAL LIFE* 



Any subject displayed systematically — as, for instance, 

 in tabular form — may be examined in two ways. We may 

 read the columns of the table vertically, or horizontally; 

 and each method reverses the principle of classification 

 upon which the other is based. Thus, in Mr. Herbert 

 .Spencer's famous sociological tables, if we take the sheet 

 •devoted to a given nation, and read the columns vertically, 

 "we obtain in each column a record of the progress of that 

 nation in some one particular, such as music, literature, 

 mechanic arts, government, social customs, etc. ; while by 

 reading across the columns horizontally, we obtain, for the 

 period represented by the line we follow, the condition of 

 the nation in all these particulars. Which way is the best, 

 depends on what we wish to study. If England in the 

 tenth century is our special subject, we read horizontally; 

 if the history of music in England is our subject, we read 

 vertically. 



Now Evolution can be exhibited in a similar way. We 

 may conceive the different departments of Cosmical, Inor- 

 ^ganic. Vegetable, Animal, Human, Social and Spiritual Ev- 

 olution as constituting the first vertical column, while in 

 other columns, under the heads of Philosophical, Geolog- 

 ical, Morphological, Endnyological, Geographical, Histor- 

 ical and Experimental, Ave nuiy give the proofs and facts of 

 Evolution for each department. Which way should this 

 table be read ? Horizontally, if we are satisfied as to the 

 truth and fully informed as to the nature of Evolution ; 

 vertically, if we wish to get the force of its evidences, and 

 a comprehension of their nature. 



In the plan of this course of lectures, the horizontal lines 

 have been followed ; and I am to speak to you to-night on 

 the Evolution of Animal Life, avoiding, as far as possible, 

 the proofs and illustrations furnished by the fossil remains, 

 the life-history, the distribution and the variation of plants. 



* CorvRiciiT, 1S80. by 'I'lie New Ideal Pul)lisliing Co. 



