PROCURING OBJECTS. 49 



the wood to be cut is fixed tightly in the square hole D ; the socket 

 put into its place and adjusted by the screw below. The knife being 

 then pushed forward will cut off a slice of wood ; upon turning the 

 wheel one tooth, and again moving the knife, a second slice will be 

 obtained, and so on. These sections, if good, should float in spirits 

 of wine. To form a proper idea of the structure of any plants, 

 three sections should be made, viz : one horizontal and two vertical, 

 one of the latter being parallel to and the other perpendicular to the 

 medullary ray. 



46. The pollen or farina from the flowers of plants, the seeds of 

 plants, the cuticles, and stomata or orifices in the cuticle, form a plea- 

 sing class of opaque objects. The spohrs of ferns, usually found in cells 

 beneath the leaf, are likewise curious opaque objects. But one of the 

 most interesting classes of botanical objects are the algze which include 

 the confervae and ftici or sea weeds. In some of the latter plants, more 

 particularly, the microscope enables us to observe the bursting of the 

 cells, the release of the sporules, which become fringed with a number of 

 cilia, by the motion of which the new being is able to traverse the water, 

 until it finds a spot fitted for its future growth, to which it then becomes 

 adherent. The same thing is observed with regard to the germ of the 

 sponge : and here we have a remarkable similarity between the repro- 

 duction of a vegetable and animal being. Some of the small disjointed 

 algze are closely allied to animalcules, in which a circulation has been 

 detected, and apparently a spontaneous motion. They are found in 

 ditches and stagnant pools. 



47. Fossil woods, when polished, are excellent opaque objects, and 

 exhibit most of the characteristics of the original plant. But by far the 

 most interesting specimens from this class of objects, are made by 

 cementing very thin sections on to sliders, which may then be viewed 

 eilher by reflected or transmitted light. 



48. MICROSCOPIC SHELLS Minute foramina, and other shells and 

 remains, form an interesting series of objects to the lovers of micro- 

 scopic research. The procuring of specimens of these minute fossils is 

 generally considered difficult. But the following method recommended 

 by Mr. Bowerbank * is simple, and within the reach of all : " If the 



* Microscopic Journal, vol. i. p. 21. 



