But substances which, like opium, laudanum, and alcohol, are not required by the body as food, or as a systematic, intelligent aid to recovery, but are taken solely for the stimulus aroused or for the insensibility induced, are harmful to man, and cannot be indulged in by him without ultimate mental, moral, and physical loss. Substances of the latter cla.s.s are known as narcotics and stimulants.

237. The Cost of Health. In the physical as in the financial world, nothing is to be had without a price. Vigor, endurance, and mental alertness are bought by hygienic living; that is, by proper food, fresh air, exercise, cleanliness, and reasonable hours. Some people wish vigor, endurance, etc., but are unwilling to live the life which will develop these qualities. Plenty of sleep, exercise, and simple food all tend to lay the foundations of health. Many, however, are not willing to take the care necessary for healthful living, because it would force them to sacrifice some of the hours of pleasure. Sooner or later, these pleasure-seekers begin to feel tired and worn, and some of them turn to drugs and narcotics for artificial strength. At first the drugs seem to restore the lost energy, and without harm; however, the cost soon proves to be one of the highest Nature ever demands.

238. The Uncounted Cost. The first and most obvious effect of opium, for example, is to deaden pain and to arouse pleasure; but while the drug is producing these soothing sensations, it interferes with bodily functions. Secretion, digestion, absorption of food, and the removal of waste matters are hindered. Continued use of the drug leads to headache, exhaustion, nervous depression, and heart weakness. There is thus a heavy toll reckoned against the user, and the creditor is relentless in demanding payment.

Moreover, the respite allowed by a narcotic is exceedingly brief, and a depression which is long and deep inevitably follows. In order to overcome this depression, recourse is usually had to a further dose, and as time goes on, the intervals of depression become more frequent and lasting, and the necessity to overcome them increases. Thus without intention one finds one's self bound to the drug, its fast victim. The sanatoria of our country are crowded with people who are trying to free themselves of a drug habit into which they have drifted unintentionally if not altogether unknowingly. What is true of opium is equally applicable to other narcotics.

239. The Right Use of Narcotics. In the hands of the physician, narcotics are a great blessing. In some cases, by relieving pain, they give the system the rest necessary for overcoming the cause of the pain. Only those who know of the suffering endured in former times can fully appreciate the decrease in pain brought about by the proper use of narcotics.

240. Patent Medicines, Cough Sirups. A reputable physician is solicitous regarding the permanent welfare of his patient and administers carefully chosen and harmless drugs. Mere medicine venders, however, ignore the good of mankind, and flood the market with cheap patent preparations which delude and injure those who purchase, but bring millions of dollars to those who manufacture.

Practically all of these patent, or proprietary, preparations contain a large proportion of narcotics or stimulants, and hence the benefit which they seem to afford the user is by no means genuine; examination shows that the relief brought by them is due either to a temporary deadening of sensibilities by narcotics or to a fleeting stimulation by alcohol and kindred substances.

Among the most common ailments of both young and old are coughs and colds; hence many patent cough mixtures have been manufactured and placed on the market for the consumption of a credulous public. Such "quick cures" almost invariably contain one or more narcotic drugs, and not only do not relieve the cold permanently, but occasion subsequent disorders. Even lozenges and pastilles are not free from fraud, but have a goodly proportion of narcotics, containing in some cases chloroform, morphine, and ether.

The widespread use of patent cough medicines is due largely to the fact that many persons avoid consulting a physician about so trivial an ailment as an ordinary cold, or are reluctant to pay a medical fee for what seems a slight indisposition and hence attempt to doctor themselves.

Catarrh is a very prevalent disease in America, and consequently numerous catarrh remedies have been devised, most of which contain in a disguised form the pernicious drug, cocaine. Laws have been enacted which require on the labels a declaration of the contents of the preparation, both as to the kind of drug used and the amount, and the choice of accepting or refusing such mixtures is left to the individual. But the great ma.s.s of people are ignorant of the harmful nature of drugs in general, and hence do not even read the self-accusing label, or if they do glance at it, fail to comprehend the dangerous nature of the drugs specified there. In order to safeguard the uninformed purchaser and to restrict the manufacture of harmful patent remedies, some states limit the sale of all preparations containing narcotics and thus give free rein to neither consumer nor producer.

241. Soothing Sirups; Soft Drinks. The development of a race is limited by the mental and physical growth of its children, and yet thousands of its children are annually stunted and weakened by drugs, because most colic cures, teething concoctions, and soothing syrups are merely agreeably flavored drug mixtures. Those who have used such preparations freely, know that a child usually becomes fretful and irritable between doses, and can be quieted only by larger and more frequent supplies. A habit formed in this way is difficult to overcome, and many a child when scarcely over its babyhood had a craving which in later years may lead to systematic drug taking. And even though the pernicious drug craving is not created, considerable harm is done to the child, because its body is left weak and non-resistant to diseases of infancy and childhood.

Many of our soft drinks contain narcotics. The use of the coca leaf and the kola nut for such preparations has increased very greatly within the last few years, and doubtless legislation will soon be inst.i.tuted against the indiscriminate sale of soft drinks.

242. Headache Powders. The stress and strain of modern life has opened wide the door to a mult.i.tude of bodily ills, among which may be mentioned headache. Work must be done and business attended to, and the average sufferer does not take time from his vocation to investigate the cause of the headache, but unthinkingly grasps at any remedy which will remove the immediate pain, and utterly disregards later injury. The relief afforded by most headache mixtures is due to the presence of antipyrin or acetanilid, and it has been shown conclusively that these drugs weaken heart action, diminish circulation, reduce the number of red corpuscles in the blood, and bring on a condition of chronic anemia. Pallid cheeks and blue lips are visible evidence of the too frequent use of headache powders.

The labels required by law are often deceptive and convey no adequate idea of the amount of drug consumed; for example, 240 grains of acetanilid to an ounce seems a small quant.i.ty of drug for a powder, but when one considers that there are only 480 grains in an ounce, it will be seen that each powder is one half acetanilid.

Powders taken in small quant.i.ties and at rare intervals are apparently harmless; but they never remove the cause of the trouble, and hence the discomfort soon returns with renewed force. Ordinarily, hygienic living will eliminate the source of the trouble, but if it does not, a physician should be consulted and medicine should be procured from him which will restore the deranged system to its normal healthy condition.

243. Other Deceptions. Nearly all patent medicines contain some alcohol, and in many, the quant.i.ty of alcohol is far in excess of that found in the strongest wines. Tonics and bitters advertised as a cure for spring fever and a worn-out system are scarcely more than cheap c.o.c.ktails, as one writer has derisively called them, and the amount of alcohol in some widely advertised patent remedies is alarmingly large and almost equal to that of strong whisky.

[Ill.u.s.tration: FIG. 161.--Diagram showing the amount of alcohol in some alcoholic drinks and in one much used patent medicine.]

Some conscientious persons who would not touch beer, wine, whisky, or any other intoxicating drink consume patent remedies containing large quant.i.ties of alcohol and thus unintentionally expose themselves to mental and physical danger. In all cases of bodily disorder, the only safe course is to consult a physician who has devoted himself to the study of the body and the methods by which a disordered system may be restored to health.

CHAPTER XXVI

NITROGEN AND ITS RELATION TO PLANTS

244. Nitrogen. A substance which plays an important part in animal and plant life is nitrogen. Soil and the fertilizers which enrich it, the plants which grow on it, and the animals which feed on these, all contain nitrogen or nitrogenous compounds. The atmosphere, which we ordinarily think of as a storehouse of oxygen, contains far more nitrogen than oxygen, since four fifths of its whole weight is made up of this element.

Nitrogen is colorless, odorless, and tasteless. Air is composed chiefly of oxygen and nitrogen; if, therefore, the oxygen in a vessel filled with air can be made to unite with some other substance or can be removed, there will be a residue of nitrogen. This can be done by floating on water a light dish containing phosphorus, then igniting the phosphorus, and placing an inverted jar over the burning substance. The phosphorus in burning unites with the oxygen of the air and hence the gas that remains in the jar is chiefly nitrogen. It has the characteristics mentioned above and, in addition, does not combine readily with other substances.

245. Plant Food. Food is the course of energy in every living thing and is essential to both animal and plant life. Plants get their food from the lifeless matter which exists in the air and in the soil; while animals get their food from plants. It is true that man and many other animals eat fleshy foods and depend upon them for partial sustenance, but the ultimate source of all animal food is plant life, since meat-producing animals live upon plant growth.

Plants get their food from the air, the soil, and moisture. From the air, the leaves take carbon dioxide and water and transform them into starchy food; from the soil, the roots take water rich in mineral matters dissolved from the soil. From the substances thus gathered, the plant lives and builds up its structure.

A food substance necessary to plant life and growth is nitrogen. Since a vast store of nitrogen exists in the air, it would seem that plants should never lack for this food, but most plants are unable to make use of the boundless store of atmospheric nitrogen, because they do not possess the power of abstracting nitrogen from the air. For this reason, they have to depend solely upon nitrogenous compounds which are present in the soil and are soluble in water. The soluble nitrogenous soil compounds are absorbed by roots and are utilized by plants for food.

246. The Poverty of the Soil. Plant roots are constantly taking nitrogen and its compounds from the soil. If crops which grow from the soil are removed year after year, the soil becomes poorer in nitrogen, and finally possesses too little of it to support vigorous and healthy plant life. The nitrogen of the soil can be restored if we add to it a fertilizer containing nitrogen compounds which are soluble in water.

Decayed vegetable matter contains large quant.i.ties of nitrogen compounds, and hence if decayed vegetation is placed upon soil or is plowed into soil, it acts as a fertilizer, returning to the soil what was taken from it. Since man and all other animals subsist upon plants, their bodies likewise contain nitrogenous substances, and hence manure and waste animal matter is valuable as a fertilizer or soil restorer.

247. Bacteria as Nitrogen Gatherers. Soil from which crops are removed year after year usually becomes less fertile, but the soil from which crops of clover, peas, beans, or alfalfa have been removed is richer in nitrogen rather than poorer. This is because the roots of these plants often have on them tiny swellings, or tubercles, in which millions of certain bacteria live and multiply. These bacteria have the remarkable power of taking free nitrogen from the air in the soil and of combining it with other substances to form compounds which plants can use. The bacteria-made compounds dissolve in the soil water and are absorbed into the plant by the roots. So much nitrogen-containing material is made by the root bacteria of plants of the pea family that the soil in which they grow becomes somewhat richer in nitrogen, and if plants which cannot make nitrogen are subsequently planted in such a soil, they find there a store of nitrogen. A crop of peas, beans, or clover is equivalent to nitrogenous fertilizer and helps to make ready the soil for other crops.

[Ill.u.s.tration: FIG. 162.--Roots of soy bean having tubercle-bearing bacteria.]

248. Artificial Fertilizers. Plants need other foods besides nitrogen, and they exhaust the soil not only of nitrogen, but also of phosphorus and potash, since large quant.i.ties of these are necessary for plant life. There are many other substances absorbed from the soil by the plant, namely, iron, sodium, calcium, magnesium, but these are used in smaller quant.i.ties and the supply in the soil does not readily become exhausted.

Commercial fertilizers generally contain nitrogen, phosphorus, and potash in amounts varying with the requirements of the soil. Wheat requires a large amount of phosphorus and quickly exhausts the ground of that food stuff; a field which has supported a crop of wheat is particularly poor in phosphorus, and a satisfactory fertilizer for that land would necessarily contain a large percentage of phosphorus.

The fertilizer to be used in a soil depends upon the character of the soil and upon the crops previously grown on it.

[Ill.u.s.tration: FIG. 163.--Water cultures of buckwheat: 1, with all the food elements; 2, without potash; 3, without nitrates.]

The quant.i.ty of fertilizer needed by the farmers of the world is enormous, and the problem of securing the necessary substances in quant.i.ties sufficient to satisfy the demand bids fair to be serious.

But modern chemistry is at work on the problem, and already it is possible to make some nitrogen compounds on a commercial scale. When nitrogen gas is in contact with heated calcium carbide, a reaction takes place which results in the formation of calcium nitride, a compound suitable for enriching the soil. There are other commercial methods for obtaining nitrogen compounds which are suitable for absorption by plant roots.

Phosphorus is obtained from bone ash and from phosphate rock which is widely distributed over the surface of the earth. Bone ash and thousands of tons of phosphate rock are treated with sulphuric acid to form a phosphorus compound which is soluble in soil water and which, when added to soil, will be usable by the plants growing there.

The other important ingredient of most fertilizers is potash. Wood ashes are rich in potash and are a valuable addition to the soil. But the amount of potash thus obtained is far too limited to supply the needs of agriculture; and to-day the main sources of potash are the vast deposits of pota.s.sium salts found in Prussia.

Although Germany now furnishes the American farmer with the bulk of his potash, she may not do so much longer. In 1911 an indirect potash tax was levied by Germany on her best customer, the United States, to whom 15 million dollars' worth of potash had been sold the preceding year. This led Americans to inquire whether potash could not be obtained at home.

Geologists say that long ages ago Germany was submerged, that the waters slowly evaporated and that the various substances in the sea water were deposited in thick layers. The deposits thus left by the evaporation of the sea water gradually became hidden by sediment and soil, and lost to sight. From such deposits, potash is obtained.

Geologists tell us that our own Western States were once submerged, and that the waters evaporated and disappeared from our land very much as they did from Germany. The Great Salt Lake of Utah is a relic of a great body of water. If it be true that waters once covered our Western States, there may be buried deposits of potash there, and to-day the search for the hidden treasure is going on with the energy and enthusiasm characteristic of America.

Another probable source of potash is seaweed. The sea is a vast reservoir of potash, and seaweed, especially the giant kelp, absorbs large quant.i.ties of this potash. A ton of dried kelp (dried by sun and wind) contains about 500 pounds of pure potash. The kelps are abundant, covering thousands of square miles in the Pacific Ocean, from Mexico to the Arctic Ocean.

CHAPTER XXVII

SOUND

249. The Senses. All the information which we possess of the world around us comes to us through the use of the senses of sight, hearing, taste, touch, and smell. Of the five senses, sight and hearing are generally considered the most valuable. In preceding Chapters we studied the important facts relative to light and the power of vision; it remains for us to study Sound as we studied Light, and to learn what we can of sound and the power to hear.

250. How Sound is Produced. If one investigates the source of any sound, he will always find that it is due to motion of some kind. A sudden noise is traced to the fall of an object, or to an explosion, or to a collision; in fact, is due to the motion of matter. A piano gives out sound whenever a player strikes the keys and sets in motion the various wires within the piano; speech and song are caused by the motion of chest, vocal cords, and lips.

[Ill.u.s.tration: FIG. 164.--Sprays of water show that the fork is in motion.]

If a large dinner bell is rung, its motion or vibration may be felt on touching it with the finger. If a tuning fork is made to give forth sound by striking it against the knee, or hitting it with a rubber hammer, and is then touched to the surface of water, small sprays of water will be thrown out, showing that the p.r.o.ngs of the fork are in rapid motion. (A rubber hammer is made by putting a piece of gla.s.s tubing through a rubber cork.)

If a light cork ball on the end of a thread is brought in contact with a sounding fork, the ball does not remain at rest, but vibrates back and forth, being driven by the moving p.r.o.ngs.