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LAMARCK, HIS LIFE AND WORK 



the animal scale in a sense the inverse of that of nature, 

 we find that there exists in the groups composing 

 this scale a continuous but irregular modification 

 {degradation) in the organization of animals which 

 they comprise, an increasing simplification in the 

 organization of these organisms ; finally, a proportion- 

 ate diminution in the number of faculties of these 

 beings. 



" This fact once recognized may throw the greatest 

 light on the very order which nature has followed in 

 the production of all the existing animals; but it 

 does not show why the structure of animals in its 

 increasing complexity from the more imperfect up to 

 the most perfect offers only an irregular gradation, 

 whose extent presents a number of anomalies or 

 digressions which have no appearance of order in 

 their diversity. 



" Now, in seeking for the reason of this singular 

 irregularity in the increasing complexity of organi- 

 zation of animals, if we should consider the outcome 

 of the influences that the infinitely diversified circum- 

 stances in all parts of the globe exercise on the gen- 

 eral form, the parts, and the very organization of these 

 animals, everything will be clearly explained. 



" It will, indeed, be evident that the condition in 

 which we find all animals is, on one side, the result of 

 the increasing complexity of the organization which 

 tends to form a regular gradation, and, on the other, 

 that it is that of the influences of a multitude of very 

 different circumstances which continually tend to 

 destroy the regularity in the gradations of the in- 

 creasing complexity of the organization. 



" Here it becomes necessary for me to explain the 

 meaning I attach to the expression circumstances 

 influencing the form and structure of animals — namely, 

 that in becoming very different they change, with time, 

 both their form and organization by proportionate 

 modifications. 



