102 
GENERAL ARRAXGEMENT. 
ters mainly to its advancement, and thus between them the 
twofold object of a National Museum of Natural History is 
carried out. 
Reserve or III. The Keserve or Study Systematic Series contains the 
Systematic exceedingly numerous specimens (in many groups the great 
Series. bulk of the collection) showing the minute distinctions required 
for working out the problems of variation according to age, 
sex, season, and locality, for fixing the limits of geographical 
distribution, or determining the range in geological time : 
distinctions which, in most cases, can only be appreciated 
when the specimens exhibiting them are kept under such 
conditions as to admit of ready and close examination and 
comparison. It is to this part of the collection that zoologists 
and botanists resort to compare and name the animals 
and plants collected in exploring expeditions, to work out 
natural history problems, and generally to advance the know- 
ledge of science. In fact, these reserve collections, occupying 
comparatively little room, kept up at relatively small cost, 
and visited by comparatively few persons, constitute, from 
a scientific point of view, the most important part of the 
Museum, for by their means new knowledge is obtained, 
which, given forth to the world in the form of memoirs, 
books, or lectures, is ultimately diffused over a far wider area 
than that influenced even by the exhibited portions of the 
Museum. Indeed, without the means of study afforded by 
the reserve series, the order displayed in arrangement, the 
exhibition galleries, and the instruction which can be gleaned 
from the same would not be possible. 
It is important to bear in mind that if the whole of such 
specimens as are really required for enlarging the boundaries 
of knowledge were displayed in the public galleries, so that 
each one could be distinctly seen, a museum many times larger 
than the present one would not suffice to contain them; the 
specimens themselves would be inaccessible to the exami- 
nation of those capable of deriving instruction from them, 
and owing to the disastrous effects of exposure to light upon 
preserved natural objects, many would ultimately lose almost 
everything that now gives them value. This portion of the 
collection must, in fact, be treated as are the books in a library. 
