BOTANICAL WORK OF THE BRITISH ASSOCIATION. 467 



support for the broad, common-sense principles on which our practice 

 should rest. 



As I suppose, everyone knows we owe our present method of nomen- 

 clature in natural history to Linnaeus. He devised the binominal, or, 

 as it is often absurdly called, the binomial system. That we must have 

 a technical system of nomenclature, I suppose no one here will dispute. 

 It is not, however, always admitted by popular writers who have not 

 appreciated the difficulty of the matter, and who think all names should 

 be in the vernacular. There is the obvious difficulty that the vast 

 majority of plants do not possess any names at all, and the attempts to 

 manufacture them in a popular shape have met with but little success. 

 Then, from lack of discriminating x)ower on the part of those who use 

 them, vernacular names are often ambiguous; thus Bullrush is applied 

 equally to Typha and to Scirpus, plants extremely different. Vernacular 

 names, again, are only of local utility, while the Linna?an system is 

 intelligible throughout the world. 



A technical name, then, for a plant or animal is a necessity, as with- 

 out it we can not fix the object of our investigations into its affinity, 

 structure, or x>roperties. (Linn. Phil., 210.) u Nomina si nescis perit 

 et cognitio rerum." 



In order to get clear ideas on the matter, let us look at the logical 

 principles on which such names are based. It is fortunate for us that 

 these are stated by Mill, who, besides being an authority on logic, was 

 also an accomplished botanist. He tells us (System of Logic, I, 132) : 

 "A naturalist, for purposes connected with his particular science, sees 

 reason to distribute the animal or vegetable creation into certain groups 

 rather than into any others, and he requires a name to bind, as it were, 

 each of his groups together." He further explains that such names, 

 whether of species, genera, or orders, are what logicians call connota 

 tive; they denote the members of each group and connote the distinc- 

 tive characters by which it is defined. A species, then, connotes the 

 common characters of the individuals belonging to it; a genus, those of 

 the species ; an order, those of the genera. 



But these are the logical principles which are applicable to names 

 generally. A name such as Ranunculus repens does not differ in any 

 particular from a name such as John Smith, except that one denotes a 

 species, the other an individual. 



This being the case, and technical names being a necessity, they 

 continually pass into general use in connection with horticulture, com- 

 merce, medicine, and the arts. It seems obvious that if science is to 

 keep in touch with human affairs, stability in nomenclature is a thing 

 not merely to aim at, but to respect. Changes become necessary, but 

 should never be insisted upon without grave and solid reason. In some 

 cases they are inevitable unless the taxonomic side of botany is to remain 

 at a standstill. From time to time the revision of a large group has to 

 be undertaken from a uniform and comparative point of view. It then 



