Progress in Science.

New Zealand Graphic, Volume XLIII, Issue 16, 20 October 1909, Page 47

Progress in Science.

The Work of the Professional • Microscopist. WILFRED MARK WEBB, F.L.S.) THOUGH not often seen in public, the microscope has its work to do in education, in science, in medicine, in commerce, in jurisprudence, to an extent which renders its duties as a popular entertainer quite insignificant. One of the best ways of getting an inkling into the subject in band is to pay a visit to a professional mounter, or perhaps we should say to several of them, for there are so many of what Mr. H. G. Wells calls “the very fine art of microtomy” that it is impossible for one man to practise {them all. We will first journey in imagination to the borders of Kew Green, Where is the laboratory of Mr. Martin J. Cole, who is known as the “younger pole,” having forsworn a nautical life—Which, nevertheless, has left its impress bn his genial character—to follow in the footsteps of his father, whose motto, “Cole Deum,” was well known to microscopists of the older generation. What Mr. Cole has to do is to cut a slice so even and so thin that when it rests on the centre of a little glass Slip, three inches by one, it is to all intents and purposes transparent. He does It in thia way: He takes a suitable piece of material which has been hardened by long keeping in strong methylated alcohol, and embeds it in the centre of a plug cut from a carrot and split into two for the purpose. This Carrot plug is made to fit into a pit in a solid but simple brass instrument, and by a very fine screw the carrot and the material can be raised to an infinitely short distance above the edge of the pit. A dexterous cut from a section ■knife, fashioned in the form of a large hollow-ground razor, and lubricated with ispirit and water, removes a thin slice. The screw is turned slightly, more or less according to the thickness of the sections required, and the process can be repeated time after time. It is necessary that the section, when obtained, should be fixed to the glass slip and protected /rom injury. The medium r ~‘~sd.

to- Tulfil the first condition varies in different cases, but it is chosen, as a irule, with a view to rendering the section even more transparent. A simple method is to remove the spirit by soaking the specimen in water and then to mount it in a drop of glycerine jelly (glycerine •nd gelatine) melted for the purpose. 'After this it is carefully covered with

an exceedingly thin disc of glass of suitable size. As the jelly cools, the glass disc is caused to adhere to the slip, but to make matters sure the slip is temporarily fastened when it is cool to the centre of a little turn-table, and while it is revolving on the latter, cement is applied with a brush so as to form a ring which covers the margin of the disc and gives the “ slide ” a neatly finished appearance. Another alternative is to mount the section in Canada balsam dissolved in benzole, chloroform, or turpen-

tine,.the specimen having been previously “ cleared ” of spirit by having been submitted to the action of clove oil. When the balsam has dried hard, there is no danger of the cover being rubbed off, but slides to be put on the market arc usua'ly “ ringed ” as already described. It is often thought necessary to bring out

certain strictures in the section by staining it with one or more dyes before it is permanently mounted. Sometimes the material is too thin or delicate to-be cut in carrot, and it may be necessary to embed it in some substance like celloidin which can be hardened round it, cut with it and dissolved away from the section when this has been

made. Celloidin may be also used to keep certain parts in their relative positions before and after they are cut, as in the case of the bud of a flower in one of our illustrations. Certain structures may be cut between the fingers with or without the help of carrot or elder pith. A very successful slide made by Mr. Cole is one showing the pollen grains of the lily sending down their tubes into the stigma of the flower which will carry down the nuclei of the grains to the eggs in the ovary below, and bring about fertilisation. Similarly on the zoological side, Mr. Cole caters chiefly for students. Occasionally he may mount animals whole when their size admits of if, as in the case of the young brittle starfish or the freshwater polyp. The cutting of animal tissues, however, is not quite such a

simple matter as that of slicing-up stems and roots, for muscle and connective tissue are more refractory under the knife. A general way 'is to freeze the pieces of tissue on a special microtons by means of an ether spray which solidifies a solution of gum placed round the object. Another way is to en’he' Hie ma-

terial in melted paraffin wax, and if the small resulting block is placed in one of the many automatic microtones, the edges of the paraffin round each section adhere to those of the one in front and behind, so that a long ribbon is formed in i: icl. the sections are arranged in their proper order. It is possible by this means to examine every thousandth part of an

inch of a small creature, and it has neen scornfully said of the laboratory naturalists who were common a yen or two ago that they might know every fraction of a creature as it appeared u section under the microscope, and yet fail to recognise it if they met it in the field. Dovetailing into the zoological work is that done for the benefit of the medical student who has to study the microscopical anatomy or histology not only of certain animals but more particularly of man. Though many of the resulting sections are exceedingly fine, there is rather a gruesome aspect about the bottles of material, or rather, one should say, their labels in some cases, for these bear th? names of the individuals whose bodies at one time or another hava found their way into th? Lona -» dis-

secting rooms. It should be said alsa that Mr. Cole's help is often invite:# by well-known surgeons who require! sections of diseased tissues which have been taken from their patients so that their cases may be diagnosed with mor# certainty. < All manner of commercial product# find their way into the laboratory, one time it may be a specimen of soms particular timber of which a section is required. At another time a series ol mantles for incandescent gas burned taxes Mr. Cole’s manipulative skill ti£ the utmost. On one occasion a largcf quantity of earth arrived with the ra* quest that some special germ shoula be found and mounted, but as to d# this would require all the apparatus an« special methods of the who would have to cultivate all th# germs present and in the end isolate the one required, Mr. Cole did not fulfil the request of the sender. One important branch of microscopical work is th# taking of photographs through the irt* strument so that magnified pictures of the various objects are obtained. Soin# workers make a speciality of this, an® it is obvious that the business mam

who does not possess a microscope or is not familiar with its use would like to have the results of an investigation in black and white. One photo-mierographer ■with whom the writer is acquainted had an interesting though difficult task allotted to him. It comprised not only the making of illustrations of a number of tiny diamonds, but also of the magnified scratches made by them. Up to the present time we have said nothing of the cutting of hard substances such as rocks and the fossils contained in tfiem, but slices often less than the two-thousandth part of an inch in thickness can be made. In this case the cutting instrument is a thin revolving disc of soft iron used with diamond dust, which, becoming embedded in the metal edge, enables the disc to cut its way through the hardest substance. An interesting branch of this work carried CP by Mr. James Lomax, of Great Levee,

Bolton, deals with the fossils of the Lower Coal Measures; and by the examination of them, by botanists, including Professor Oliver and Dr. Scott, the origin of some of our modern plants has been traced. Apart from their use foy original research and for teaching purposes, these sections of fossil plants are used in museums to illustrate their structure and the natural history of coal. From the figure which we owe to the courtesy of Mr. Lomax, even those who are not familiar with the microscopical anatomy of recent plants will recognise the great amount of detail which can be seen and portrayed. We may pass over the use of the microscope for determining the origin of blood stains and for detecting adulterations in food and other things. The whole science of bacteriology and the discovery of disease germs is dependent upon the microscope, but except when sections are needed showing bacilli in situ in the tissues the help of the microtomist is not required, for the bacteriologist finds that the mounting of his specimens when he has once obtained a pure culture, is the easiest part of his work. In passing, we may just say that modern dairying and brewing, to mention no other industries, are indebted to the microscope to a tremendous extent. In the colonies wools are examined microscopically instead of by rule of thumb methods. Agriculture also in Europe has gained greatly from a knowledge of soil bacteria and the organisms living in the nodules on the roots of members of the pea family, enabling the latter to use nitrogen obtained from the air instead of from the soil. In conclusion a word may be said with regard to fancy mounting, by which one means the arrangement of diatoms and forarninifera in ornamental patterns; the making of microscopic baskets from the tiny arid inany-hued scales of butterflies which delight the heart of amateur microscopists and visitors to such conversaziones as we alluded to at the beginning of the article. The reducing of photographs to such an extent that they cannot be seen without a microscope may bo considered at this point, as well as the extremely minute writing on slides with a diamond, which some few individuals have been able to do. The most celebrated of these was a namesake of the present writer, lie was a hunchback through an injury, and ho had been told that he would only live for a certain number of years. This idea became so fixed on his mind that he

used to urge Messrs. Watson and Sons, the opticians, to take as many slides as possible, as he had only just so long to live. On the day before the last year allowed him was completed he betook himself to a hospital without saying anything to his wife, went to bed, and the next day he was dead, though previously he was apparently as well in health as he had been for many years. ❖ <s><s> Women Warders to Reform Criminals. “Many people are criminals to-day because they lacked a mother’s care when they were young,” says Dr. Anna Howard Shaw. “Few people,” she continues, “are criminals by nature. They are generally such by accident, and if, after they had taken the first wrong step, there had been a woman to care for them, instead of a man to control them, their lives might have taken a different trend. Why are the reformatories not more successful, despite all the care an 1 money which is expended on them? Why do they fail in very many instances to achieve their purpose, which is, of course to reform the youthful criminal? It is because there are too many men in them and too few women. Of course, I do not blame the men wholly. They doubtless do the best they can, and are as anxious to reform criminals as the members of the opposite sex. The trouble is they lack the instinct which makes every woman a mother in circumstances of a peculiar kind, and which urges her to take a personal interest in individuals that would be almost impossible for men.” <s><?><& The First Radium Congress to be Held Next Year. For the first time since radium claimed the attention of the world of science an international congress will be held to discuss its wonderful properties. It is planned to hold the congress next year in Brussels, and it is supposed that new secrets and new wonders will be revealed. Mme. Curie has promised to take part in the congress and to make known important recent discoveries by the French savants. It is expected that England will be largely represented. <s><§><§> Astonishing Adulteration of Tea Leaves. It seems, from experiments in the Chinese tea-grow'ing districts, that the flower of the tea plant is much to be preferred to the leaf. The infusion of the flower is very sweet, and has the same stimulating qualities as the infusion of the leaves. Moreover, the flower contains only about two per eent cafferin, while the leaf contains as milch as four per cent. Tea leaves must be picked one by one; the flowers, on the contrary, are collected much more simply. The principal quality of the flower is the difficulty of imitating it. Imitations of leaves are innumerable. Most astonishing adulterations of tea leaves are practised in China. The oak, the eglantine, the ash, the strawberry, the laurel, the cherry, the chestnut, the olive, the elm, the apple, and the plum —in fact, almost every tree that grows • —offers its leaves freely to unscrupulous dealers for mixture. Even ordinary wood sawdust, properly coloured, has been employed. Fancy - teas are adulterated with clay and other mineral sub-tanceS. The tea flower is more or less proof against imitation. ❖ <?><s> Wind Power. If the wind blowing over London to a height of S(H) feet could be harnessed, Mr. Sidney Ransom estimates, it would do work equivalent to that of a steam engine of half a million horse-power, working day and night. Wind turbines can be used for many purposes, are simple to erect, and do not usually require towers more than 59 feet high. In Germany, a wind-power electric generating equipment has been brought out. No attention is needed except to reduce the sail area of the wind wheel in storms, a storage battery holds the excess current from the dynamo until needed, and a special regulator automatically keeps at constant pressure the current supplied for house-lighting or driving small farm or other machines.

Queer Parisian Dishes. Among the queer dishes now consumed in Paris are fried lizards and young crocodiles and snakes. According to statistics, 5000 common lizards are sold in Paris every year, and those who make it a special calling to supply this commodity find it very profitable. But there is a far greater demand for salamanders, which are a special kind of lizard. Some 8000 of these are disposed of every year. Young, and therefore tender, lizards frequently fetch as much as a small chicken—about 3/6 apiece. Snakes feteh a good price, too, and good ones are worth as much as a turkey. Adders, it seems, are considered a special ddlieaey, and are most in demand. Young crocodiles also find a good market. They are nearly as dear as a good-sized calf, and when very small they fetch fancy prices. -$> <S> <s> The Mysteries of Coffee, Horrible disclosures have just been made on the Continent of methods in common use for the “manufacture of coffee.” It seems that of factories for that purpose existing in France there are 106 which turn out 24,000 tons annually, while there are 568 such establishments in Austria-Hungary, including 412 for the manufacture of coffee from figs, and in Germany nearly 15,000 hands are employed in the trade, and the annual output is 100,000 tons. It follows that a large quantity of “coffee” which we drink has not an atom of the real berry in it. The list of substances out of which it is manufactured is alarming. Cereals soaked with beer, brandy, or rum, chestnuts and horsechestnuts, haricot beans and broad beans, carrots, dates, and, finally, the hard roe of eod. The annual output of what is charmingly called “fanciful coffee” is estimated at over 257,000 tons.