Common Objects for the Microscope. 469 
haps, that everything is the result of an eternal and immu- 
table law, or rather of a combination of such laws, acting 
blindly, and evolving by mere chance results which simu- 
late the workings of an intelligent mind ; such a theory as 
this seems to be opposed to all analogy, and to destroy the 
basis of all reasoning, since if, in this case, where the ana- 
logy can be supported by such innumerable instances, the 
argument from it does not hold good, there can be no 
means of proving anything which we do not know of our 
own certain knowledge, we can believe in the existence of 
nothing which we do not see with our own eyes. Enough 
of this; the writer only wishes to address those who are 
prepared to see, in the wonderful works of Nature, sure 
proof of the infinite wisdom and goodness of God. 
In the present paper, it is proposed to point out a few 
objects of beauty, that can be easily procured, and which, 
when procured, can be prepared without difficulty for obser- 
vation. 
The great class of Echinodermata, which includes the sea- 
urchins, the star-fishes, and the sea-cucumbers, which are 
found upon our coasts, affords to the microscopist a vast 
number of objects of extreme beauty and interest. The 
animals of this class possess an external skeleton, com- 
posed of a multitude of plates of carbonate of lime, 
arranged often in a very beautiful manner, and furnished 
with spines and other curious appendages, varying in the 
different families. 
Let us take a specimen of Ophiocoma Rosula, a species 
of brittle star, very common on our coasts ; by placing it in 
a moderately strong solution of potash we shall be able to 
dissolve away all its soft parts, so that nothing will remain 
but the skeleton, composed of an immense number of 
separate pieces; this skeleton itself, if nicely freed by the 
potash from all organic nature, forms a very beautiful 
ornament. The five long tapering arms are densely covered 
with spines of considerable size; if some of these are 
separated and placed under a low power of the microscope, 
they will be found to present an extremely lovely appear- 
ance. They ave slightly curved, and taper from base to 
point; they are serrated along their curved borders, the 
serrations being rather long and pointing upwards. The 
smaller and more delicate spines that are situated towards 
the end of the arm are most beautiful; they are more 
transparent than the larger ones, are not curved so 
much, and the serrations are larger in proportion to the 
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