LECTURE XXXIII. 

 ARE SPECIES REAL ? 



"Systematic work would be easy were it not for 

 this confounded variation, which, however, is pleasant 

 to me as a speculatist, though odious as a systematist. 

 . How painfully true it is that no one has a 

 right to examine the question of species who has not 

 minutely described many. . . . Certainly I have 

 felt it humiliating, discussing and doubting and ex- 

 amining over and over again, when in my mind the 

 only doubt has been whether the form varied today or 

 yesterday. . . . After describing a set of forms as 

 a distinct species, tearing them up and making them 

 separate, and then making them one again (which has 

 happened to me), I have gnashed my teeth, cursed 

 species, and asked what sin I had committed to be so 

 treated." Darwin. 



Variation of Species. Does one species change into 

 another ? The crucial test of the theory of the forma- 

 tion of species by natural laws. 



The old idea of species. From Linnaeus's " Systema 

 Naturae " (1758). The idea of variety. Homo sapiens, 

 the aboriginal man, and the five varieties : Europseus, 

 Asiaticus, Afer, Americanus, and Monstrosus. Homo 

 troglodytes, the orang-outang, a second species of man, 

 according to Linnaeus. 



Fallacy of old ideas discovered by a close compari- 

 son of species. Lamarck. Darwin. 



