when subjected to the action of alkali and heat, whilst in other cases that body cannot be procured. This chemical fact gives two divisions—(1) The albuminous, or proteine principles; (2) The gelatinous. The former can be obtained from the vegetable as well as the animal kingdom, but the latter are only found in the animal world, as gelatine from bones and chondrine from cartilage; these latter also do not contain phosphorus. All the nitrogenous aliments must undergo digestion before they can enter the system; and to enable them to be absorbed, they must be liquefied and transformed. It is according to the ease and rapidity with which these processes are effected, and the forces which can be obtained from the changes which their elements undergo, that their value as diets depend. The changes are promoted by digestion, commencing with mastication. The process is completed when the aliment has become changed into peptones, or 'albuminose,' as it has been styled by Lehmann and Mialle. Albumen in the coagulated form is dissolved, and is not again coagulable. Fibrine is dissolved. Caseine is curdled, and then re-dissolved; and gelatine is liquefied. All together by the aid of the gastric juice. they form chyme, and mixing with the pancreatic and intestinal juices, go through the several changes which are terminated by the reception of the valuable part of the metamorphosed food into the current of the circulation, and the rejection of the useless débris from the body. The value of the material supplied is regulated by its power to assist in (1) development; (2) renovation, and in (3) the promotion of the functions of vitality which are evolved in the manifestation of the attributes of the special senses. Nitrogenous matter, forming the instrument of living action, is continuously disintegrated, and the resulting debris is being continuously removed. The smaller the debris the greater the value of the food, and the less the chance of the living machine being clogged by useless matter. It used to be assumed that nitrogenous matter was the only source of muscular power, but it has been clearly shown that it is not produced by muscular destruction, as Liebig supposed, and that nitrogenous matter is not supplied through muscle, but, at the same time, it has been also proved that a plentiful supply of it does increase the power of an individual to perform muscular work. This is effected by the direct utilisation of the carbon and hydrogen which it contains. The elimination of urea, as the debris of nitrogenous matter is called, and which is excreted by the urine, is related to the quality of the food supplied, and not to the muscular work performed; and more recent observations tend to show that the metamorphosis takes place in the liver, and not in muscle. (To be continued.) Friedrich Fröbel. BY HIS PUPIL, HEINRICH HOFFMAN. IX. No wonder that so few were equal to such a task. Middendorf, however, had a wonderful way of maintaining his independence, and yet really submitting. And well he might; were there not so many points in which they were altogether one? That simple-minded earnest piety, that firm clinging to the eternal Bible truths, that unbounded love of mankind, that tender affection for little children, and last, not least, that sublime disinterestedness-were all equally marked in each of them. Middendorf was a child among children; Fröbel was spell-bound in the presence of a child. The sight of one, even at a distance, would act on him like a loadstone and would draw him a good distance out of his way, that he might have a friendly chat. Their stay at Griesheim, however, was but short. There was nothing specially advantageous in that locality, beyond the fact that, of their six pupils (for Middendorf had brought with him Langethal's brother), three could live at home with their mother. But on the expiration of the customary privilege, allowed to widows of clergymen, Frau Fröbel purchased a small farm at Keilhau, a short distance west of Rudolstadť. A locality better adapted for educational purposes, it would certainly not be easy to discover. It is just as if nature had on purpose done her wisest and her best to produce a combination of the highest educational advantages. Fröbel's keen eye saw at once the realisation of his long-cherished dream, an ideal picture, that had often delighted his imagination. In June; 1817, they removed to the farmhouse. Frau Fröbel followed them some months later, when her own house had been thoroughly repaired. The two friends had fully expected work, very hard work; but little did they know what difficulties they were to encounter. We, in our days, are so accustomed to the luxury of school architecture and school appliances, that the tale of such privations, such extreme discomfort as they had to endure, seems to us utterly incredible. What with premises all but uninhabitable-if a mere carcase, minus doors, windows, and flooring, can in courtesy be called premises a season of unprecedented misery, a disastrous famine raging over all Germany, and the utter absence of pecuniary resources-more than once they had to thank Mrs. Fröbel even for their bread-it is, indeed, a wonder how they held out. But, fortunately, the woods abounded in wild. strawberries and other delicacies of nature, and the boys were not over-fastidious. Did they not live in a country where fruit formed the principal ingredient of the meals of all the villagers, with the purest crystalline beverage fresh from the public well? a herring or a fried sausage being a private luxury enjoyed only by paterfamilias, when on market-days business called him to Rudolstadt. New premises had to be built. In their poverty they endeavoured, as best they could with their own hands, to make their miserable abode habitable. They managed to obtain a schoolroom, rent free, compared with which all our grand palatial buildings. are but pigeon-holes. It extended over an area more than two German miles in circumference, and it included mountains and hills and woods and rivulets, and the most delightful scenery; together with a library that was positively inexhaustible in its rich and wonderful treasures. And just as in an ordinary schoolroom, the broom and the cleaning brush are essential means of civilisation, so Middendorf took good care to leave behind him traces of culture, wherever he came with his boys. Wherever there was a fine view there they erected seats. They eased the ascent of steep hills, laid out walks, planted trees. When they found a brooklet they searched for its spring, and bridged the stream at convenient points. On their return home with their rich harvest of flowers and curiosities of the mineral world, Fröbel was in his very element in classifying and naming the specimens thus collected. At the fall of the year Langethal joined his friends, 'to share with them,' as Middendorf has it, 'the tormentingly delightful fate of a sublime sphere of labour amidst extreme exertions and almost incredible privations.' He was, indeed, an invaluable addition. A high reputation both as regards ability and character preceded him, for he had passed his theological examination with brilliant success. He was determined to devote himself heart and soul to Fröbel's work, and soon became a great favourite with the boys, who admired his manliness, his prowess in gymnastic exercise, his inexhaustible store of knowledge of history, and especially of the romantic lore of the Middle Ages. Winter set in, and closed their delightful out-door schoolroom. They had to pull down and to rebuild with their own hands the stoves, to avoid being suffocated by the smoke. The pupils increased in number, and so did their cares and difficulties, but equally so their courage and their invincible ardour. The thought of earning money had never entered their minds. That they should share alike in the work, in the expenses, and in the earnings, was too much a matter of course to require much of an agreement Their faith in the idea that guided them was too great to be shaken by outward obstacles. It was enough for them that the young tree had struck powerful roots. It was a matter of deep regret to them all when Frau Fröbel was obliged to leave Keilhau. She moved to Volkstädt, and Fröbel became, by purchase, owner of the farm. All felt that a mother's superintendence of the increased household was now indispensable, but it required all the buoyancy of his spirit, all the courage and the unremitting faith of Fröbel to induce him to think of marrying. And yet, ever since his inspectorate at Berlin, he cherished in his innermost heart the memory of a lady, who had made a deep and lasting impression on him. It was Wilhelmine, daughter of Herr Kriegsrath, Councillor of War, Hoffmeister, a lady of high intellectual attainments, of the purest and noblest aspirations, large-hearted, and enthusiastically devoted to philanthropic labours. In the company of her father, she had been a frequent visitor at the museum. Fröbel, in his animated manner, had there revealed to her a rich vein of intellectual treasures. The earnestness of his mind, his high aspirations, the grandeur of his character, could not fail to excite her admiration. He had never forgotten those interesting conversations, and frankly divulging to her his position and the state of his affairs, he ventured to ask her to his humble home. She readily consented to give up a life of comfort and luxury with the refined enjoyments of a high social circle, and joined him on his thorny path on the 20th of September, 1818, the anniversary also of her birth. (To be continued.) The New Class-Subject, 'Elementary Science.' (What to teach, and how to teach it.) BY RICHARD BALCHIN. CONTINUING the scheme of lessons for Standard III., as given in the February issue of the PRACTICAL TEACHER, we now come to the subject-matter of Chapter VI., ie, 'Useful Vegetables.' LESSON 21.-CORN. Objects exhibited: Specimens of common grasses, and of wheat, oats, barley, rye, and rice. Picture of flour-mill, etc. (Note.-By pasting together sheets of cartridgepaper, I have made a number of paste-boards four feet long and eighteen inches wide. These are stiff On enough to stand up on end before the class. these cards I have mounted the specimens above alluded to, and they make really attractive objects. It is easy to obtain good specimens three to four feet high of such grasses as-Triticum repens,' to compare with wheat; 'Holcus lanatus' fully out, to with oats; 'Poa trivialis' and 'Poa pratensis,' compare 'Lolium perenne,' etc. The specimens of corn are similarly mounted. In my old British school, over twenty boys had themselves made collections of grasses, named and mounted. But this was before the advent of the Code.) First note that all kinds of corn are but cultivated grasses. Distinguish, by means of the specimens, between wheat and barley, and between oats and rice. Describe, conversationally, the operations-(1) Sowing, (2) Reaping, (3) Threshing, and (4) Grinding. Notice the general composition of this kind of food, i.e., make a little wheaten dough; knead it in the hands while a boy pours over it a little cold water; the water runs off 'milky' in appearance, due to the presence of starch. What remains is mostly gluten, rather sticky. Pour a little of the milky water into a test-tube, and add a drop or two, not more, of iodine solution; the starch-water turns blue. LESSON 22.-POTATOES AND GREENS. Objects exhibited: A potato, a good 'hearted' cabbage cut in halves; picture of same; a bread grater, and iodine solution; also, if possible, a horse-radish and carrot. For a good dinner, we generally have with the meat potatoes and greens. Potato, from the root of the potato-plant; not itself a root. Compare potato with carrot; the eyes' of the former are 'buds,' i e., leafbuds. No buds on the carrot, only fibres. Hence, potato not a root, really a kind of underground stem, called a 'tuber.' Horse-radish, like the carrot, is a root. Show section of cabbage; really a great leafbud. Central stem (axis) trying to force its way up. If the cabbage 'runs to seed' it does so force its way up and bears flowers and seeds. Wash out the starch from the potato, as described on page 116 of the 'Science Reader' for Standard IV. Note. The subject-matter of Lessons 23 to 27 is fully given in the 'Reader' for Standard III. LESSON 28. THE PLANE AND SYCAMORE. Objects exhibited: Pictures of these trees; specimens of their leaves and of their fruits. Carry on a conversation about the pictures, noting, 1st, the points of likeness between these trees, i.e., both have smooth woody trunks and spreading branches; both large ornamental trees; leaves very nearly the same pattern in both; wood light-coloured and durable, easily worked. 2nd, Points of dissimilarity. The fruit of the plane quite unlike that of the sycamore. On the plane the flowers and fruits are in ball-clusters on pendulous stalks; two or three balls on each flowerstalk to each flower in the cluster there is a seedcase, containing one or two seeds. The green flowers of the sycamore are thickly clustered around a pendulous stalk; not many of the flowers really producing seeds; sometimes only four or six in each cluster. The fruit is a pair of winged seed-cases, joined at their swollen ends. If such a pair be thrown up into the air, it spins round and round, hence the childish name-dicky birds.' Plane trees are often planted in school playgrounds, or by the side of the road in large towns. They are on the Thames Embankment. This tree is a native of North America. It comes in leaf after the sycamore. The bark often peels off in cakes, leaving white patches on the trunk. The sycamore is really a maple, and should be called the sycamore-maple. LESSON 29.-THE OAK. Some Objects exhibited: Pictures of the oak-(1) A tree grown naturally; (2) A pollard oak, ie., one whose central stem has been cut for the purpose of inducing it to throw out branches around the section. oak-leaves and wood, acorns, oak-galls, and a sharp penknife. Also, if possible, an infusion of oak-galls, made by breaking up three or four of them and soaking in hot water; a little of the solution of sulphate of iron (copperas). point of all liquids-the mercury in the thermometer, for instance. Boiling-point of water, 212°; not shown on ordinary thermometer; not long enough. Heat of healthy body, 98°. Mix some broken ice and water; place the glass in the water; mercury sinks to 32°. Mix some broken ice and salt; mercury sinks below 32°. Place in this mixture the little test-tube, with a small quantity of water in it. The water is frozeni.e., ice and salt, a freezing mixture. Boil some water in an empty oil-flask over a spirit-lamp; describe the behaviour of water when boiling. To show how upward currents are produced, introduce a finely-pointed glass-tube, containing a little thick black ink, so as to allow a small stream of ink to run out into the water in the lower part of the flask. The ink will be carried upward, and for a time remain quite distinct from the water. The subject-matter of Lessons 37 to 42 is fully given on pages 74 to 94 of the 'Reader' for Standard III. and on page 73 of the 'Reader' for Standard IV. LESSON 43.-NATURE'S WORK. Objects exhibited: Picture of a country scene during a storm, or during a shower; the one illustrating a rainbow will answer the purpose. Allow the boys to talk freely about the picture; leading them to note (1) the downpour of rain and then its effects-ie., (a) washing the streets or roads; carrying away material to the gutters, then to the sewers, to the rivers, to the sea. The same with the general surface of land, i.e., removing the land to ponds, or lakes, or river-deltas, or to the sea. (b) Clearing the air of impurities, such impurities being brought down to the earth to become food for plants. All such work is done independently of man. It is Nature's work. (2) Note that the rain comes from the clouds. Clouds are masses of water-vapour, which have been raised from the surface of the earth to the air by the sun. Sunshine, drying up the streets, etc., after a shower. Many tons of water fall as rain; therefore many tons of water lifted into the air by the A great work. Not man's work; it is one of the great works of Nature. (3) Note the trees, grass, flowers, and corn all living, feeding, and growing. Mostly the work of the sun. The sun's heat brings out the buds and leaves of spring, forms the summer blossoms, and ripens the autumn fruits. Not alto sun. Compare the oak with the plane or sycamore (1) As to trunk: oak, rough, often gnarled; plane, smooth; trunk of pollard oak very large, often hollow. (2) As to shape of leaves. Oak not planted by road-side. Why? Very slow growth. Two kinds of flowers on the oak; only one kind comes to acorns. Compare vegetable marrow and cucumber. (Better not use the technical terms for these unisexual blossoms. Call the staminate flowers 'pollen flowers,' and the pistil-gether the work of man, who only assists in the great late ones fruit flowers.') Seems to be two kinds of fruit on the oak-tree, ie., acorns and oak-galls. Oakgalls not a fruit. It is a case made by an insect, in which to lay an egg. Egg comes to a grub or maggot, which eats its way through the case and becomes a small fly. Cut open a few galls to illustrate this. Note that the steel knife is blackened. Put some clear infusion of galls in one test-tube, and some clear solution of copperas in another, pour the two together into a third tube, and so make black ink. The subject-matter of Lessons 30 to 36 is given with sufficient fulness in the 'Reader.' LESSON 37-WATER FREEZING And Boiling. Objects exhibited: A thermometer; some ice and salt; can of water; a basin; a narrow test-tube. An empty oil-flask, and retort-stand. A spirit-lamp and a piece of pointed glass tube (ie., a pipette). Carry on conversation about the thermometer. Note the freezing-point of water, 32°; this is not the freezing work of the sunshine and the shower. LESSON 44.-'THE WORK OF THE SUN.' First: Ripening Fruits and Seeds. Show the sprouting grain. Describe the spring wheat appearing and growing, as the work of the spring sun. Then the hot sun of August ripens the grain. Note the difference between the fruit and the seed. Cut the apple open and show the seeds. Call the fruit the 'seed-case.' Give other illustrations of this, i.e., show the seeds in the grape or the gooseberry. With such fruits as the apple, orange, plum, grape, etc., the ripening' is really the formation of sugar in the substance of the plant or fruit. Instance the terms grape-sugar,' 'cane-sugar,' etc. This 'sugarmaking' is the work of the sun. Note that starch is formed before sugar. (To be continued.) 1 Physiology. BY ARTHUR NEWSHOLME, M.D. LOND., Gold Medallist and University Scholar, Physician to the City Dispensary. CHAPTER VIII.-(continued). The liver is situated under cover of the ribs on the right side of the body, fitting into the concave surface of the diaphragm. It is the largest gland in the body, measuring from ten to twelve inches transversely, and weighing in the adult an average of from fifty to sixty ounces. It is solid to the feel, and of a dull reddish brown colour. It is imperfectly divided into a right and left lobe, and the right lobe shows three secondary lobes or lobules. The surface is covered, like that of most of the abdominal organs, by the peritoneum, and certain folds of the peritoneum form ligaments fixing the liver in position. Inside the peritoneum is a coating of areolar or fibrous tissue, which at the portal fissure (that is, the place where the portal vessels enter the liver) becomes continuous with a fibrous sheath, known as the capsule of Glisson, enveloping the portal vein, hepatic artery, and hepatic duct as they branch in the substance of the liver. It will be convenient before describing the intimate structure of the liver to enumerate its vessels and ducts, and show how they are connected with the alimentary canal. On the under surface of the liver can be seen two small ducts which bring the bile from the substance of the liver. They join together to form the hepatic duct (Greek, hepar, the liver), as seen at b, Figure 39. The hepatic duct is joined at an acute angle by the cystic duct, which is one and a of an inch between its coats, and finally entering the intestinal canal. The liver is supplied with blood from two sourcesthe portal vein, and the hepatic artery. The portal vein brings the blood from most of the alimentary canal, and from the spleen; it enters the substance of the liver along with the hepatic artery and the hepatic duct; and the three together run in small canals, called portal canals, which are each invested by a portion of Glisson's capsule. The substance of the liver is made up of a multitude of minute lobules, varying from a half to one line in diameter. These are polyhedral masses not completely isolated from one another; each one consisting of a mass of cells penetrated by a close network of blood capillaries, and by the capillary commencements of the bile ducts. The cells composing the main mass of the lobules are from to inch in diameter, polyhedral in shape, each containing a clear round nucleus, and one or two nucleoli. The cell substance is granular and of a faint yellowish tinge; occasionally fat globules are also visible. The cells are packed round the vessels, and when seen in a cross-section appear as if radiating from the centre of the lobule towards its circumference. The exact nature of the origin of the bile ducts is somewhat doubtful. It has been already stated that the larger bile-ducts accompany the branches of the portal vein, and ramify with them in the outer part of each lobule. There can be little doubt, however, that they penetrate the substance of the lobule, and that here biliary capillaries are formed, which between the lobules form minute biliary ducts, and join with others, finally leaving the liver as the hepatic ducts. It is still doubtful whether these biliary capillaries have distinct walls of their own, or are mere channels between the individual cells of the lobule. The portal vein in its course through the liver breaks up into capillary vessels, an event which is only paralleled in the case of the veins leaving the Malpighian tufts of the kidney. It first gives off small branches, accompanying those of the hepatic duct, which divide again and again between the lobules, and are hence called the inter-lobular veins. From these small veins a dense capillary network penetrates the substance of the lobule, which gradually collects itself into a larger vessel at the centre of the lobule, called the Fig. 39-Showing relation of ducts opening into duodenum. (a) Gall-bladder. (6) Hepatic duct. (c) Opening of a pancreatic duct. (d) Opening of a tube formed by junction of common bile duct and a pancreatic duct. (e) Duodenum cut open to show orifices of ducts. (f) Common bile duct. () Pancreas, also cut across in part of its course to show the commencement of ducts. half inches long, and brings the bile from the gallbladder. The gall-bladder lies on the under surface of the liver, being fixed to it by areolar tissue. It forms a reservoir in which bile is collected until required in the intestine; and it is probable that the stimulus furnished by the passage of food over the orifice where the common bile duct opens into the intestine, is sufficient to cause a contraction of the involuntary muscular fibres in the wall of the gall-bladder, and consequently an expulsion of its contents. The common bile duct formed by the junction of the hepatic and cystic ducts, is nearly three inches in length, and passes down to pierce the duodenum near its middle, running obliquely for three-quarters Fig. 40.-Cross-section of a lobule of the human liver, magnified six times. 1. Intra-lobular vein cut across. 2. Its smaller branches gathering blood from the capillary network. 3. Inter-lobular veins, with ramifications passing inwards to form the capillary network. The hepatic artery is distributed in a similar manner to the portal vein, its function being to supply nutriment to the tissues of the liver. The Pancreas lies within the curve formed by the duodenum, and behind the stomach. It is usually from six to eight inches long, and its weight is variable, but usually about two and a half to three ounces. In its general characters and minute structure, the pancreas closely resembles the salivary glands, belonging to the class of compound racemose glands. The duct by which its secretion is poured into the alimentary canal is well shown in Figure 39. It runs through the walls of the intestine side by side with the common bile duct, and terminates by a common opening in the mucous membrane. Occasionally part of the sacculi open by a duct at a separate point of the duodenum. (3) £567 18s. 6d. + £4920 6s. 10d. +£51783 195. 11 d. +2202 16s. old. +£2867 15s. 71d. (Given partly in words). Ans. £62,342 175. od. (4) £9001 14s. 91d. - £183 15s. 10 d. (words). Ans. £8817 18s. 10d. STANDARD IV. (1) Take 5000 farthings from 5000 shillings. Ans. £244 15s. 1od. (2) Out of 16 cwt. of butter, a grocer sells 27 lb. daily for 5 days. How much has he still on hand? Ans. 14 cwt. 3 qrs. 5 lbs. (3) Divide £8 8s. old. equally among 109 men; how much will each get? Ans. Is. 6d. (4) Bring 17 sq. yds. 8 sq. ft. 120 sq. ins. to sq. ins. Ans. 23,304 sq. ins. (1) (13) of)+(1 of 33) -735. (2) Bring of 1 25. 11d. to the fraction of of £3 12s. 14d. Ans. (3) Multiply 0132 by 021, then divide the result by '00084. Ans. $33. (4) Find the simple interest of £10 3s. 4d. for 31 years at 2 per cent. Ans. 175. 94d. (1) 609 (2) (3) (4) 915 618 (1) A lady went a-shopping with £10 in her pocket. spent 19s. 6d. in groceries, 7s. 9d. in boots, and £5 os. 11d. in dresses; how much money had she left ? Ans. £3 11s. Iod. (2) Divide ninety-three thousand one hundred and two by ninety-five. Ans. 980--2. Ans. 124 B., 164 G., 112 I. (3) A dealer buys toys at 1os. a gross, and sells them at a penny each; find his gain per cent. Ans. 20 per cent. (4) The discount on a bill due 10 months hence at 6 per cent. is £70. Find the amount of the bill. Ans. £1470. Domestic Economy. STAGE I. (1) What is flax? What materials are made from it ? (2) What advantages have knitted stockings over woven ones? (3) What should be done with the lines and pegs after the clothes are taken in from the drying yard? (4) What kind of clothes should be worn in summer, and what kind in winter? Why? (5) What foods contain respectively albumen, fibrine, gluten, and casein ? (6) What foods contain fatty substances? |