REPORT OP THE SECRETARY. 41 



and preserved in the Patent Office with other samples of the protected 

 jiroducts of original thought, namely : models of invention and speci- 

 mens of design. 



Two douole cases, each fifty feet in length, have been provided 

 during the present year, which, with the previous shelves, will be 

 sufficient to hold the books at present in the library and those which 

 may be received for some time to come. 



Museum. — It has been stated in previous reports that it is not the 

 design of the Institution to form a general museum of all objects of 

 natural history, but of such as are of a more immediate interest in 

 advancing definite branches of physical research ; and in view of this, 

 special attention has been bestowed on developing the peculiarities of 

 the productions of the American continent, with a view to ascertain 

 what changes animals and plants have undergone, how they differ in 

 their present as well as their past forms from those on other portions of 

 the globe, and also the distribution of the same species, and the rela- 

 tions which they bear to the soil and climate where they are found. 

 The great object of studies of this class is to determine the laws of the 

 production^ growth, and existence of living beings. The nature of life 

 itself is at present unknown to us, except in its relation to certain or- 

 ganic forms and changes going on in them. It is, to our apprehension, 

 insep9,rably connected in this world with transformations of bodies 

 chemically composed of a few elementary materials, which are con- 

 stantly being combined and decomposed, in accordance with laws 

 peculiar to the living being. In reference to the forms which these 

 materials assume, the whole animal kingdom has been referred to 

 four great types or plans of structure, the Vertebrata, the Articulata, 

 the Mollusca, and the Kadiata. From these four types all the varieties 

 that are found on the surface of the earth are derived. It appears to 

 be a principle of nature that the most diversified effects are made to 

 follow from a single conception, a fact which is well expressed by the 

 terms " multiplicity in unity." Whilst every part of the earth is 

 peopled with animals constructed in accordance with these types, the 

 fauna of no two parts of the world are precisely alike. Difierence in 

 conditions of climate or soil, or difference in original character, have 

 produced a diversity, the nature of which is an important object of the 

 naturalist to investigate. For example, fishes of the same name, and 

 apparently of precisely the same character, found on the east and west 

 sides of the Eocky mountains, present peculiarities which, though 

 slight, are invariable, and which mark a difference of origin or of 



