252 Agassiz 1 Contributions to the 



isties of the species, even though it be hermaphrodite, neither do 

 any two represent it, even though the species be not polymorph- 

 ous, for individuals have a growth, a youth, a mature age, an old 

 agv, and are bound to some limited home during their lifetime. 

 It is true species are also limited in their existence; but for our 

 purpose, we can consider these limits as boundless, inasmuch as 

 we have no means of fixing their duration, either for the past 

 geological ages, or for the present period, whilst the short cycles 

 of ihe life of individuals are easily measurable quantities. Now 

 as truly as individuals, while they exist, represent their species 

 for the time being, and do not constitute them, so truly do these 

 same individuals represent at the same time their genus, their 

 family, their order, their class, and their type, the characters of 

 which they bear as indelibly as those of the species." 



In this general statement, with the explanations elsewhere given 

 of it, in relation to the capacity of species for intermixture, and 

 the supposed original creation of numbers of representatives of the 

 same species in different places, we see much that is objection- 

 able, and a want of that accuracy of thought which is essential 

 in treating of such a 'subject. 



First, we cannot admit the high standing here given to the 

 individual animal. The individual is here confounded with an 

 entirely different thing, namely, the unit of the science. As 

 has been well stated above, the individual rarely represents the 

 species as a whole. To give this we have to employ a series 

 of individuals, including the differences of age and sex, and the 

 limits of variation under external circumstances. The individuals 

 representing these varieties are therefore only fractional parts of a 

 unit, which is the species. Let it be observed, also, that the rela- 

 tion here is different from that which subsists between the species 

 and the genus. Each species should have all the generic charac- 

 ters with those that are specific; but each individual, as a frac- 

 tion of the species, need not necessarily possess all the mature 

 characters of the species; and this is one reason of the indistinct 

 notion in many minds that the limits of species are more uncer- 

 tain than those of genera. On the other hand, the idea of specific 

 unity is expressed by our attaching the specific name to any indi- 

 vidual that we may happen to have ; and even popular speech 

 expresses it when it says the grisly bear, the Arctic fox. 



Secondly, the species is not merely an ideal unit : it is a unit in 

 the work of creation. No one better indicates than our author 



