XX. 



ON CATAGENESIS.* 



I. THE EVOLUTION OF OEGANISMS. 



The general proposition that life has preceded organization in 

 the order of time, may be regarded as establislied. It follows ne- 

 cessarily from the fact which has been derived from paleontological 

 investigation, that the simple forms have, with few sporadic ex- 

 ceptions, preceded the complex in the order of appearance on the 

 earth. The history of the lowest and simplest animals will never 

 be known, on account of their perishability ; but it is a safe infer- 

 ence from what is known, that the earliest forms of life were the 

 rhizopods, whose organization is not even cellular, and includes 

 no organs whatever. Yet these creatures are alive, and authors 

 familiar with them agree that they display, among their vital 

 qualities, evidences of some degree of sensibility. 



The following ^propositions were laid down by Lamarck, as 

 established by facts known to him, in 1809 : f 



I. "In every animal which has not passed the term of its de- 

 velopment, the frequent and sustained employment of an organ, 

 gradually strengthening it, develops and enlarges it, and gives- it 

 power proportional to the duration of its use ; whilst the constant 

 disuse of a like organ insensibly weakens it, deteriorates it, pro- 

 gressively reduces its functions, and finally causes it to disappear. 



II. " All that nature acquires or loses in individuals, through 

 the influence of circumstances to which the race has been exposed 

 for a long time, either by the predominant use of an organ or by 

 the disuse of such part, she preserves by generation among new 



* An address delivered before the Biological Section of the American Associa- 

 tion for the Advancement of Science, at Philadelphia, September 4, 1884, by E. D. 

 Cope, vice-president. 



t "Philosophie Zoologique," Pt. I, p. 235 (Edit. 1830). 



