154 CORRESPONDENCE. 



real addition to knowledge. Its present state has led to the dis 

 covery, that the globe was once occupied by other inhabitants than 

 the present. Whence the species of our time have come, it is not 

 for us to say. We find them allotted in different sets to different 

 portions of the earth, each individual species spreading as far as 

 its own organic structure permits. 



But maritime intercourse is changing the face of things. The 

 different races of mankind are brought into unexpected contact 

 and are supplanting each other on every hand. Plants in vast 

 variety, as well as animals, are transferred from their native clime 

 to seize upon a foreign soil. 



The productions of small islands, though not numerous, are ex 

 tremely interesting ; more especially, when widely separated from 

 a continent. Such often contain peculiar animals and plants , 

 animals, too, of very considerable size. The huge, helpless tor- 

 toise of the Galapagos,, could not have kept up its race on a con- 

 tinent, or on an island inhabited by man, were it at all noxious, or 

 even useless. It is now nearly certain, that during the short period 

 Europeans have been acquainted with the great ocean, a clumsy 

 animal of the ostrich kind has entirely disappeared. Whether it 

 is, that in a wide extended field the number of species has been 

 reduced by the same process of mutual extermination, this is most 

 certain, that the variety is by no means in proportion to the surface. 



With regard to the organization of the zoological department, I 

 would remark, that as the range is sa ample, several observers will 

 be required ; and much might be gained by a distribution of the 

 branches. No one individual can do justice to all parts of zoology 

 life is too short, even in the absence of other considerations. 

 The department would be lame, indeed, without some one versed 

 in the internal structure of animated beings. One or more good 

 natural-history draughtsmen are indispensable, and the requisite 

 qualifications are very rarely to be met with. The mechanical 

 part of collecting and preserving should be well provided for : all 



