38 n. WHAT IS A SPECIES ? 



into orders and genera, the groups thus formed by bota- 

 nists are in no sense equivalents of each other, either 

 structurally or numerically, although designated by the 

 same term. 



Have botanical Species an existence in nature more 

 real and definite than the groups above named? Per- 

 haps without exception every technical botanist will 

 afiirm that species have such an existence ; that they are 

 realities in nature, as definite and distinct in their way as 

 the Man and the Chimpanzee, or the Tiger and the Lion, 

 are believed to be by ordinary observers. But technical 

 botanists, — that is to say, describers of genera and spe- 

 cies, — are seldom profound reasoners ; and those cultiva- 

 tors of science, who wish to have sound reasons for the 

 faith that is in them, will do better by examining the 

 practices, than by accepting the opinions of the mere 

 describers of species, so many of whom are unequal to 

 any higher object in science. 



Two questions are involved in an inquiry as to the 

 reality of species. It may first be asked, whether species 

 do actually exist in nature ? And secondly comes the 

 inquiry, whether botanists know the species so existing, 

 or supposed to exist ? Although essentially distinct in 

 kind, the two queries are practically inseparable. We 

 cannot reply to the first question positively and logically 

 in the affirmative, unless we can also answer the second 

 question positively and certainly. The only certainty 

 that species do exist in nature, definite and distinct from 

 each other, must be derived through our knowledge of 

 them as true species. If it should appear, on rigorous 

 investigation, that we do not know such and such assem- 

 blages of individuals to be species, according to our ab- 

 stract definition of the term species ; but that we only 

 infer from incomplete data and proofs that they are so ; 



