MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. 385 



In the description of species, our young naturalist had shown that he could 

 discern and describe Avith exactness and clearness the most minute characteristic 

 traits. These qualities, so necessary to the zoologist, arc seen in the work of 

 which we speak. Already he had shown a sort of innate tendency to ascend 

 from the details to the whole, to connect isolated facts with general principles. 

 For example, in speaking of the- caudal development of mammalia, the author 

 does not content himself with noting the very considerable variations presented 

 by tlie number of vertebra? which compose it. He aims to take account of them, 

 and ibr this purpose ascends to the pheuomenaof their first formation. He reminds 

 us that in the human embryo, the coccyx, until the end of the sccoikI month, 

 is quite as long as the tail of the dog of similar age. He agrees with M. Serres 

 in attributing to a retreat about the upper pai-t of the spinal marrow, the arrest 

 of development which in the human species intercepted the appendage so prom- 

 inently developed in the dog. He compares these facts with those presented 

 by the tadpoles of the frog and the toad, and concludes by saying: "Thus the 

 mammal is metamorphosed like the batrachiau, and all the changes which 

 surprise us in the latter are not even anomalies ; they take place equally in the 

 mammal, and in man himself; and are the general phenomena of embryogeny." 

 All the- anatomical and desci-iptive part of the Avork is executed in the same 

 spirit. , 



The hairy coating of mammalia, the variations of color that distinguish races, 

 the influence of domestication on external chai-acters, the result of the crossing 

 of species and races, likewise conduct Isidore Geoffroy to general considera- 

 tions, the greater part of which had escaped his predecessors. In several 

 passages we see the dawn, more or less advanced, of a great number of ideas 

 which, ripened by reflection and continued study, served as the basis of the 

 great Avork of Avhich Ave shall speak hereafter. 



An order of considerations Avhich occupies an important place in this work, 

 and wliieh we cannot pass Avithout notice, is that Avhich embraces zoological 

 geography. From the philosophic point of A'ieAv Avhcre the son of Etieune 

 Geofl^roy had placed himself at twenty-one, the grandeur and truthfulness of 

 the conceptions of ButTon on this subject could not escape him. We can see 

 that he has been deeply impressed Avith them ; that already he has been seeking 

 to A'erify them by ficts; and that if he undertakes the defence of his illus- 

 trious predecessor, it is Avith a full knoAvledge of the subject. This enlight- 

 ened conviction, which Isidore Geoffroy shared Avith his father, is e\'inccd in 

 many of his other Avritings. If the unjust prejudices inspired by the Linna^an 

 doctrines, imperfectly understood, have been partly dissipated ; if, in our day, 

 naturalists admit Buffon to be still greater as a savant than as a writer, it is 

 certainly in great part due to the efforts of these tAvo peneti-ating minds, so 

 well formed to comprehend, develop, and inculcate a right appreciation of 

 Avhat had too long been misunderstood in the genius of their predecessor. 



The complete list of the works of Isidore Geoffroy, already published in 

 this bulletin, renders it unnecessary for us to enumerate here several treatises 

 of dilFerent kinds Avhich succeeded each other rapidly until 1832. We shall 

 merely point out the tendency, more and more marked in their author, to sub- 

 ordinate facts of detail to complete vicAvs, and to attach himself to general 

 and philosophic zoology, such as had been comprehended, though from dif- 

 ferent points of vicAv, by Buffon, Lamarck, and Etieune Geoffroy. These 

 prevailing ideas were manifested officially,, as we may say, in a course of 

 lectures given at the Athenaeum in 1830, Avhich turned entirely on the funda- 

 mental relations of the animal species among themselves and to the external 

 Avorld. By this course of lessons, which had no precedent in public instruc- 

 tion, Isidore Geoffroy began to assume his special place in the phalanx of 

 those Avho foUoAved the same banner with himself, and was not long in placing 

 himself in their foremost rank. Tavo years later appeared the first volume of 

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