78 ON VARtKTiES, lUCJiS, bUiJ-Si'liOlES, AND SPbClES. 



comprised in a given species of living bodies, when it is wished 

 fo unite them into different groups, the mutual relations of 

 which, being susceptible of variation in different degrees, give 

 rise to what y/e have designated ti/pes of species j or simply types^ 

 varieties, races-, and sub'-species. These distinctions express the 

 most general relations of all the individuals grouped into what 

 is at present called a species, independently of any question as to 

 origin, and are simple and concise formulas which possess the 

 double advantage of giving the naturalist a means of clearly 

 expressing his opinion on the relations which he observes in the 

 individuals composing the species of which he speaks, and of 

 furnishing the critic v/ith a means of communicating his thoughts 

 when he wishes either to cite or discuss the different opinions of 

 naturalists on the subordination of the individuals of a given 

 species. 



If the application of one of these five distinctions to any given 

 species should be found impossible, let this fact be expressed by 

 the letter Omega attaclied to the species ; no letter should how- 

 ever be annexed to any species until tlie latter has luidergone the 

 examination of which we speak. 



The great advantage that v/ill result from the adoption of the 

 above system of notation v,'ill be, tiiat all the species marked at 

 first Omega, or nothing at all, will attract the attention of all 

 observers, who will then know on what points information is 

 required. 



§ III.— VEGETABLE SfECIES CONSIt)ERED WITH UESPECT TO 

 BOTH THEIR PERMANENCE AND TENDENCY TO BE MODIFIED, 



In treating, in the First Part, of the definition of a species, we 

 have admitted in principle that known facts do not permit us to 

 consider tlie actual circumstances, in which organized bodies at 

 present live, as sufficiently powerful to alter their specific essence, 

 because we have no example of indivitluals of one species giving 

 rise to an individual of another species ; and, besides, notwith- 

 standing the extent of the modifications which living bodies have 

 undergone within our own knowledge, they always differ from 

 their parents less than any other individuals of a different 

 epecies do. 



To be able to judge of the use of the definition of species given 

 by us, and founded on experiment, we must see how it stands 

 with respect to the five preceding distinctions, when we take into 

 account the modifications v/hich the different species of living 

 bodies can undergo without losing their respective peculiarities. 



If it is evident that the more numerous the parts or distinct 

 organs of a living being are, the more numerous will be the pos- 



