MICROSCOPIC OBJECTS.] 



UNDULATORY FORCES. LIGHT. 



kingdom for microscopic study ; and in it the analogies 

 between vegetable and animal structure hold a prominent 

 place. As we have already remarked, it will be impos- 

 sible for us to give more than general hints ; and the 

 directions we have given in reference to mounting animal 

 objects, are equally applicable to those obtained from 

 plants, <kc. 



The fungi BO continually formed on decayed sub- 

 stances vary in size, from those requiring a microscope 

 to detect their presence, to those of the mushroom and 

 larger kinds, with which all are familiar. Some of these 

 present very beautiful appearances under the microscope, 

 and are therefore well worthy of the attention of the 

 student. 



Ascending to the higher classes of vegetables, we ob- 

 serve the most interesting traces of analogy between 

 plants and animals. The leaves take the place of lungs ; 

 the solid fibre that of bones ; the sap is as the blood ; and 

 we might thus continue to connect the two kinds of ex- 

 istence by an almost continuous chain. It will be suf- 

 ficient for our purpose to indicate some of the leading 

 points of resemblance between the two kinds of vital 

 existence; and we therefore append a synopsis of the 

 most easily recognised subjects. 



The cells of all plants perform a similar office to that 

 of the veins of animals, as the sap which is the blood of 

 plants is propagated to every part by their agency. 

 The existence and appearance of the cells may be observed 

 by cutting a thin slice off any branch or stem. The form 

 of the cell, and the arrangement of the successive rings, 

 vary in each tree ; so that they are really characteristic, 

 form beautiful microscopic objects. 



The woody fibre or solid portion of plants is, as it 

 were, their flesh, bone, and muscle, and differs, in its 

 physical character, in every production of the vegetable 

 kind. Thus we have the strong and close fibre of the 

 oak and ash, and the delicate fibres of the cotton plant. 

 The fibrous matter of grasses is easily obtained by soaking 

 the leaf in a little solution of carbonate of soda, and then 

 immersing it in some very dilute sulphuric acid. Each 

 filament will split from its neighbour, and thus may I..- 

 nepuratcly examined. 



Flf. U. 



represents granules of rice lurch ; , gruuln of MCO starch ; r, the 

 rranulet of wheat starch ; d, granules of potato starch ; , the name, 

 bat more mwtmrt. J ; /, the granules of lout let mois starch ; f. Is the 

 same starch after being heated, by which the granules are burst open ; 

 A, U a specimen of pea starch. 



The leaves of trees, <fec., present a very interesting 

 appearance, and the green matter may easily be separated 

 from the fibre, and so produce the net-work in a separate 

 state. There are few more beautiful objects than these 

 fur exhibition in the oxy-hydrogen microscope; aud for 

 that purpose the currant tribe of leaves is to be pre- 

 frrn-'l. 



The cuticle or skin of plants is analogous, in its office, 



to the animal skin. Hairs, down, pores, ike. , may be 

 detected in the leaves of most plants, the pores 

 being very numerous on them, and serving the double 

 office of respiratory and perspiratory organs. 



In some, or most grasses, in wheat, barley, and oats, a 

 silicious skin is observed, which is composed of minute 

 crystals of silica or flint. A coarse and rank grass, 

 growing in stagnant ponds, affords it in considerable 

 quantities. 



Starch is a substance abounding in all plants, and pre- 

 sents a variety of appearances when the granules are 

 obtained from vegetables. Fig. 65 illustrates the form of 

 some varieties. 



We need not remind our readers, that flowers are 

 interesting objects for microscopic investigation, and their 

 variety affords an almost endless field for research. The 

 seeds and fruits of all kinds of plants are equally interest- 

 ing ; and perhaps the most instructive matter to which 

 we can direct the attention of the student, is that of the 

 process of germination, from the first change of the starch 

 into sugar, until the radicle has made its appearance on 

 the outside of the seed. We must not, however, enlarge 

 here on this subject, because we shall have to enter fully 

 into the consideration of these points in our section on 

 Botany. 



In the mineral kingdom, we find less variety of objects 

 than in those on which we have been treating. Tliis is 

 partly owing to what we venture to term a comparative 

 monotony of external form which exists therein, in con- 

 trast to the infinite variations of animated structures. 

 The mineral, in fact, forms the raw material, which, 

 in the hands of the Creator, has been fashioned 

 into life. Organised existence, indeed, depends on the 

 arrangement of but few elementary bodies. The means 

 are surprisingly limited ; whilst the number of products 

 is only bounded by the skill of Him who in wisdom hath 

 made them all. 



There are, however, many points of interest to be dis- 

 covered in the mineral kingdom, more especially in re- 

 ference to the molecular and crystalline structure of 

 bodies. It is true that we cannot perceive those ultimate 

 atoms of which a mass is composed ; but, as the power of 

 our microscope is increased, so we can often detect the 

 existence of definite forms utterly unpurccivable by the 

 naked eye. A moat remarkable instance of this is found 

 in tho discovery of Professor Ehrenberg, who has detected 

 the presence of exceedingly minute shells in common 

 chalk ; which indicates that that substance is simply the 

 remains of an immense destruction of animalcules, whose 

 exuviro are now the only testimony of their previous 

 existence. Similar facts have been brought to light 

 during the examination of the bed of the Atlantic, pre- 

 paratory to laying the electric cable between this country 

 and America. Quantities of what appeared at first to have 

 I" .'it wand, turned out to be the shells of marine insects, 

 which had gradually accumulated in such quantities, as 

 to present a bed thousands of miles in superficial area, 

 and of considerable depth. 



ID geological researches, the microscope is of great 

 value in determining the character of some strata, by the 

 examination of the materials of which it is composed; 

 and similarly, in the study of mineralogy, the amorphous 

 or crystalline nature of masses can be detected. We 

 shall, however, defer for the present any details on these 

 subjects, reserving our remarks until we deal with them 

 in their proper sections. 



We have thus endeavoured to give some general idea 

 of the diversified objects which fall under our notice, as 

 subjects of microscopical examination in tho three king- 

 doms the animal, vegetable, and mineral ; and conclude 

 by saying, that our observations can only bo regarded 

 as indicating the nature, rather than the extent, of 

 valuable knowledge which the microscope opens out to 

 our understanding and examination. 



TELESCOPES. 



THE next optical instrument to which we shall call 

 attention is the telescope, with its various modifications 



