C. A. Ealand

“ To the microscopist who merely uses his microscope for the pleasure he can derive from it, rather than for serious study, it may appear that the plant life of the sea falls short of the animal life as far as interest is concerned. He may disabuse himself at once of this idea. There is no class of plants more interesting than the seaweeds and in few branches of plant life is there greater scope for new discoveries. The garden of the sea is largely an unexplored territory and there is no coast-line in the world of equal extent which provides so many different sea dwelling plants as our own. ”

“ Geology, as the science of rocks is called, is no more difficult than botany or zoology, the sciences of plants and animals respectively. Botany and zoology, however, appeal in some degree to nearly all of us; we may learn a good deal concerning the structure of the cockroach with the help of our microscope and be interested in the revelations of our instrument, but to embark on a detailed course of the minute internal anatomy of insects would appeal to few of us. Animal or plant life may be studied piecemeal and enjoyed on account of its absorbing interest. ”

“ THE MICROSCOPE AND INSECT LIFE Some of our readers will probably remark that entomology, or the natural history of insects, is really a branch of zoology and should be treated as such. We cannot pretend that they are wrong, but it is such a specialized branch that it merits separate treatment. Not many years ago insects, with few exceptions, were looked upon as harmless and often beautiful dwellers upon the earth. ”

“ Given an unlimited quantity of a substance for testing purposes it is not always easy to determine its composition. With very small quantities, perhaps less than a tea-spoon full in all, the difficulties of the analyst are increased tenfold and without the assistance of the microscope his efforts would be unavailing, he deals in drops and every drop is precious. Sad to relate this form of testing, known to science as micro-chemical analysis, has been practised to a far greater extent on the continent than in this country. ”

“ There are thousands of plants with hairy leaves and they will provide as many interesting objects for our microscope. Let us examine as many as we can for the hairy covering of each plant will be a little different to the one we examined previously. There are simple hairs, quite ordinary affairs, forked hairs, branched hairs, T-shaped, star-shaped and club-shaped hairs. If we are clever with our microscope we shall notice that, however complex each hair may be it is really nothing but one cell of the skin of the leaf which has assumed a peculiar shape. ”

“ In the plant world, many fossils in amazingly, good states of preservation have been found. Some of the giant Club Mosses from the coal measures, exhibit all the characteristic stem markings, leaf scars and the like, so clearly that one might imagine one examined a living specimen. Most of the plant remains are beyond the reach of the amateur, but many of them may be viewed in museums, in different parts of the country and the microscopist, whether he be a student of rocks or a lover of plants, should make a point of examining them. ”

“ No man will ever see all that the microscope can show him, each day some fresh wonder is looked upon for the first time.
As a hobby, microscopy can hardly be excelled. It is a sensible hobby and, after the initial outlay, need cost us but a few pence each year. We hear someone say that he prefers an outdoor hobby, but surely the microscope, if used intelligently, will take [308] us out of doors. The search for specimens is one of the attractions of microscopy. As an instrument for the serious worker the microscope compares favourably with any other invention of mankind. ”

“ Any luckless creature, coming within reach of the Hydra, is at once stung with one of the barb-shaped stings which stud his tentacles and then passed to his mouth. The Hydra is wonderfully tenacious of life ”

“ THE MICROSCOPE AND PLANT LIFE The science of botany consists of many branches and, in most of them, the microscope is the scientist’s constant aid. The study of bacteria, really a branch of botany, we have dealt with in another chapter, so here we will omit these interesting though lowly plants. By far the number of botanical objects for the microscope consist of sections—exceedingly thin slices of whatever portion of the plant is being examined, cut either with a sharp razor or a special instrument called a microtome. ”

“ Not unlike the water flea as it swims about in the water of our collecting jar is the curious, transparent little creature known as Cypris. Although so transparent its body is contained in a pair of shells, very similar to those of the mussel; a fact which formerly led to its being classed with the shell-fish. We may well examine this little fellow under the microscope for much of his structure may be made out through his shell. His very conspicuous eye is sure to attract our attention; he possesses but a single eye and seems to make up for the lack of a second by having a very large one. ”

“ In time all the little particles became welded together to form a new kind of rock. Sometimes animals and plants were buried in the mud destined to become a rock and their parts were so well preserved that they may not only be recognised by present-day scientists, but in many cases their structure may be made out so well with the aid of a microscope that no one would guess they had been buried thousands of years ago.
New rocks have been formed not only by the breaking up and welding together of the original earth’s crust, but by animal and plant remains. ”

“ THE MICROSCOPE BY THE SEASIDE—ANIMAL LIFE It is always surprising that the majority of microscopists never dream of examining any of the hundreds of beautiful objects which can be found by the seaside, in the course of an afternoon’s ramble. ”

“ The smuts are very important but are not of much interest as objects for the microscope, so we will pass them over for subjects of greater interest if of less importance.
Every farmer knows the familiar and destructive fungus known as “rust of wheat,” it is one of a large class of most interesting plants. The “rusts” are interesting to the microscopist on account of their structure and to the botanist because they cannot, like other fungi, complete their lives upon one plant. They derive their popular name from the fact that they look like patches of rust upon the plants on which they live. ”

“ Having examined the adult liver fluke under the microscope, we shall probably wish to find both the free swimming young forms, and if we search carefully in ponds to which sheep have access we are likely to be rewarded. It is obvious that the life of a parasite such as the liver fluke is, of necessity, precarious. It is only chance or luck, or whatever one’s favourite term may be, that brings the egg to water, the young fluke to a snail, and the last free swimming form to herbage that will be eaten by a suitable animal. ”

“ In the mud of our pond we may find a little colony of plants which might forgivably be mistaken for a collection of the individuals we have just studied. Each member of the colony is very much smaller than Chlamydomonas to be sure, but each one has the outer membrane, the brownish eye spot and the pair of little whips. On the other hand the chlorophyll fills the whole of each cell and is not arranged in the form of a cup. Sixteen cells form a colony, and the whole mass is a flat plate; the little whips move in unison and the whole colony revolves after the manner of a wheel. ”

“ Suppose we take milk, water, butter, anything in fact upon which bacteria will grow and examine them carefully. If we have the requisite knowledge and recognise what we see, we shall find not one kind of bacterium but a number of different bacteria. Now by certain manipulations, which need not be described here, all the different kinds of bacteria may be sorted out, so that we have colonies consisting of one kind of bacterium only and such a colony is known as a “pure culture.” ”

“ By scraping the newly cut surface of a potato we can obtain thousands of starch grains. The surface of the potato must not be grated, just a gentle scraping with a pocket knife and a mere speck of the cloudy liquid that is obtained, added to a drop of clean water on our slide, will suffice. Cover the object with a cover glass and examine under a fairly high magnification. There are countless, oval, almost transparent bodies in our field of view, they are potato starch grains. Each one, as we shall see when we make a more careful examination, is not unlike a miniature oyster-shell. ”

“ That every pond will contain ample material for study, the microscopist knows instinctively; insect life and plant life also he studies, but the microscope is generally left at home when a visit is paid to the seaside. A rocky coast is better than a sandy one, for rock pools yield many objects, and the warmer southern waters of our coasts are better than the colder northern seas, but the microscopist who finds himself on a northern sandy coast need not despair, if he search diligently he will find material enough to occupy him for many a day. ”

“ The most important question concerns the choice of a microscope. In a book of this nature it is obviously impossible to recommend the wares of any one maker. Some firms are celebrated for the good wearing qualities of their instruments, some for the delicacy—not fragility by the way—of their fine adjustments and our readers must select their maker for themselves. One thing we strongly advise, be patriotic and select a British maker, it is not only a question of patriotism but of self interest, for in many respects the British instruments lead the world. ”

“ If we examine some raw silk, taken from the middle layer of a cocoon, we can easily see the two parallel fibres of silk and the outer wrinkled covering of silk glue. Now, magnifying our object more highly, we shall see that each fibre is a solid rod, with a smooth lustrous surface and without any sign of lumen or cell structure; the rods too are continuous and this alone distinguishes silk from all other fibres animal or vegetable. ”

“ Having taken our fill of the spiders’ feet we may well turn our attention to their heads. If we have caught a spider in the act of killing a struggling fly, it must have struck us that one bite from the spider is sufficient to kill its victim. Let us see if we can find the jaws which so quickly bring death even to large insects. We shall require a steady hand and some little skill to examine them properly but the task is not beyond our powers. Having killed our spider we must snip off its head, place it on a slide and examine it with a low magnification. ”

“ In each cell we shall see signs of activity, the little round grains of chlorophyll are there, but instead of being stationary, as in the cabbage leaf, they are slowly moving round the walls of each cell. In reality they are carried along in the stream of living matter within the cell. It is a wonderful sight and brings home to the observer very forcibly a fact which is liable to be forgotten, that the plant is just as much a living being as an animal. Perhaps our experiment will not succeed at the first attempt, then we must try again ”

“ Sometimes we find a simple pair of claws on each foot, in other cases each claw has a little spur, whilst spiders, which, by the way, are not insects, have comb-like claws. The foot of the house-fly is not only provided with a pair of claws, but also with a soft fleshy pad, by means of which it is enabled to climb window panes and similar smooth surfaces. If we are fortunate enough to obtain a specimen of a louse, human or otherwise, we must not fail to notice its strong grasping claw, used for taking a firm hold of the hair of the creature on which it lives. ”

“ Very frequently the results of costly law cases hang on the reports of expert food examiners; every care, therefore, must be taken to avoid error. This being the case, whenever possible, chemical tests should be carried out to confirm the results of microscopic examination. When both microscopist and chemist come to the same conclusion, there is not likely to be any mistake. There are tests which the microscope cannot perform, there are some, also, which are beyond the powers of the chemist and many which are very difficult for him. ”

“ When white light passes through a prism of glass, it is not only bent out of its course, but broken up into all these colours. A prism, as we all know, when examined at either end, is seen to be triangular in shape. Putting aside for a moment the question of the breaking up of light into its component parts, the path of [44] a ray of light through a prism is shown in the diagram. As the ray passes from air into glass it is bent, because glass is more dense than air; it is bent once more on leaving the prism because air is less dense than glass. ”