LAMARCK: SCALE OF BEING 217 



determinations of species, and how artificial the classificatory 

 groups which we distinguish in Nature. Strictly speaking, 

 there are in Nature only individuals, ". . . this is certain, 

 that among her products Nature has in reality formed neither 

 classes, nor orders, nor families, nor genera, nor constant 

 species, but only individuals which succeed one another and 

 resemble those that produced them. Now, these individuals 

 belong to infinitely diversified races, which shade into one 

 another under all the forms and in all the degrees of 

 organisation, and each of which maintains itself without 

 change, so long as no cause of change acts' upon it " (p. 41). 



But there is a natural order in the animal kingdom, 

 a progression from the simpler to the more complex 

 organisations, a natural Echelle des etres. 



This order is shown by the relation to one another 

 of the large classificatory groups, for they can be arranged in 

 series from the simplest to the most complex, somewhat as 

 follows : 



1. Infusoria. 6. Arachnids. 11. Fishes. 



2. Polyps. 7. Crustacea. 12. Reptiles. 



3. Radiates. 8. Annelids. 13. Birds. 



4. Worms. 9. Cirripedes. 14. Mammals. 



5. Insects. 10. Molluscs. 



But the order of Nature is essentially continuous, and the 

 limits of even the best defined of these classes are in reality 

 artificial " if the order of Nature were perfectly known 

 in a kingdom, the classes which we should be forced to 

 establish in it would always constitute entirely artificial 

 sections " (p. 45). 



In the same way the lesser classificatory groups represent 

 smaller sections of the one unique order of Nature. Note 

 that Lamarck's Eclielle is in no way a morphological one, 

 and was not intended to be such. It is a scale of increasing 



o 



physiological differentiation, and the stages of it are marked 

 by the acquirement of this or that new organ (cf. Oken). 

 " Observation of their state convinces one that in order 

 to produce them successively Nature has proceeded gradually 

 from the simpler to the more complex. Now Nature, having 

 had in mind the realisation of a plan of organisation 



