A Practical Physiology Part 43

mixtures.

_Carbolic Acid:_ Creasote. Severe pain in abdomen; _No emetic._ Milk or odor of carbolic acid, flour and water; white of mucous membrane in eggs.

around mouth white and benumbed; cold and clammy skin.

_Aconite:_ Wolfsbane Numbness everywhere, _Vomit patient freely._ Monkshood great weakness; cold Stimulating drinks.

sweat.

_Belladonna_ Deadly Nightshade Eyes bright, with pupil _Vomit patient freely._ Atropia enlarged; dry mouth and throat.

_Various Vegetable Poisons_ Wild parsley, Stupor, nausea, great _Cause brisk vomiting_.

Indian tobacco, weakness and other Stimulating drinks.

Toadstools, symptoms according to Tobacco plant, the poison.

Hemlock, Berries of the mountain ash, Bitter sweet etc.

393. Practical Points about Poisons. Poisons should never be kept in the same place with medicines or other preparations used in the household.

They should always be put in some secure place under lock and key. Never use internally or externally any part of the contents of any package or bottle unless its exact nature is known. If there is the least doubt about the substance, do not a.s.sume the least risk, but destroy it at once. Many times the unknown contents of some bottle or package has been carelessly taken and found to be poison.

Careless and stupid people often take, by mistake, with serious, and often fatal, results, poisonous doses of carbolic acid, bed-bug poison, horse-liniment, oxalic acid, and other poisons. A safe rule is to keep all bottles and boxes containing poisonous substances securely bottled or packed, and carefully labeled with the word POISON plainly written in large letters across the label. Fasten the cork of a bottle containing poison to the bottle itself with copper or iron wire twisted into a knot at the top. This is an effective means of preventing any mistakes, especially in the night.

This subject of poisons a.s.sumes nowadays great importance, as it is a common custom to keep about stables, workshops, bathrooms, and living rooms generally a more or less formidable array of germicides, disinfectants, horse-liniments, insect-poisons, and other preparations of a similar character. For the most part they contain poisonous ingredients.

Bacteria.

394. Nature Of Bacteria. The word bacteria is the name applied to very low forms of plant life of microscopic size. Thus, if hay be soaked in water for some time, and a few drops of the liquid are examined under a high power of the microscope, the water is found to be swarming with various forms of living vegetable organisms, or bacteria. These microscopic plants belong to the great fungus division, and consist of many varieties, which may be roughly divided into groups, according as they are spherical, rod-like, spiral, or otherwise in shape.

Each plant consists of a ma.s.s of protoplasm surrounded by an ill-defined cell wall. The bacteria vary cably in size. Some of the rod-shaped varieties are from 1/12,000 to 1/8,000 of an inch in length, and average about 1/50,000 of an inch in diameter. It has been calculated that a s.p.a.ce of one cubic millimeter would contain 250,000,000 of these minute organisms, and that they would not weigh more than a milligram.

[Ill.u.s.tration: Fig. 168.--Examples of Micro-Organisms called Bacteria.

(Drawn from photographs.)

A, spheroidal bacteria (called _cocci_) in pairs; B, same kind of bacteria in chains; C, bacteria found in pus (grouped in ma.s.ses like a bunch of grapes).

[Bacteria in A, B, and C magnified about 1000 diameters].

D, bacteria found in pus (tendency to grow in the form of chains).

[Magnified about 500 diameters.]

Bacteria are propagated in a very simple manner. The parent cell divides into two; these two into two others, and so on. The rapidity with which these organisms multiply under favorable conditions, makes them, in some cases, most dangerous enemies. It has been calculated that if all of the organisms survived, one bacterium would lead to the production of several billions of others in twenty-four hours.

395. The Struggle of Bacteria for Existence. Like all kinds of living things, many species of bacteria are destroyed if exposed to boiling water or steam, but seem able to endure prolonged cold, far below the freezing-point. Thus ice from ponds and rivers may contain numerous germs which resume their activity when the ice is melted. Typhoid fever germs have been known to take an active and vigorous growth after they have been kept for weeks exposed in ice to a temperature below zero.

The bacteria of consumption (bacillus tuberculosis) may retain their vitality for months, and then the dried expectoration of the invalids may become a source of danger to those who inhale air laden with such impurities (sec. 220 and Fig. 94).

Like other living organisms, bacteria need warmth, moisture, and some chemical compound which answers for food, in order to maintain the phenomena of life. Some species grow only in contact with air, others need no more oxygen than they can obtain in the fluid or semi-fluid which they inhabit.

396. Importance of Bacteria in Nature. We might well ask why the myriads of bacteria do not devastate the earth with their marvelous rapidity of propagation. So indeed they might, were it not for the winds, rains, melting snow and ice which scatter them far and wide, and destroy them.

Again, as in countless other species of living organisms, bacteria are subject to the relentless law which allows only the fittest to survive.

The bacteria of higher and more complex types devour those of a lower type. Myriads perish in the digestive tract of man and other animals. The excreta of some species of bacteria act as poison to destroy other species.

It is true from the strictest scientific point of view that all living things literally return to the dust whence they came. While living they borrow a few elementary substances and arrange them in new combinations, by aid of the energy given them by the sun, and after a time die and leave behind all they had borrowed both of energy and matter.

Countless myriads of bacteria are silently at work changing dead animal and vegetable matter into useful substances. In brief, bacteria prepare food for all the rest of the world. Were they all destroyed, life upon the earth would be impossible, for the elements necessary to maintain it would be embalmed in the bodies of the dead.

397. Action of Bacteria. In certain well-known processes bacteria have the power of bringing about decomposition of various kinds. Thus a highly organized fungus, like the yeast plant, growing in the presence of sugar, has the power of breaking down this complex body into simpler ones, _viz._, alcohol and carbon dioxid.

In the same way, various forms of bacteria have the power of breaking down complex bodies in their immediate neighborhood, the products depending upon the substance, the kind of bacteria, and the conditions under which they act. Thus the _bacteria lactis_ act upon the milk sugar present in milk, and convert it into lactic acid, thus bringing about the souring of milk.

[Ill.u.s.tration: Fig. 169.--Examples of Pathogenic Bacteria. (Drawn from photographs.)

A, spiral form of bacteria found in cholera (Magnified about 1000 diameters) B, rod-shaped bacteria (called _bacilli_) from a culture obtained in _anthrax_ or malignant fustule of the face. Diseased hides carry this micro-organism, and thus may occasion disease among those who handle hides and wool. (Magnified about 1000 diameters) ]

Now, while most species of bacteria are harmless, some are the cause of sickness and death when they gain admittance to the body under certain conditions. These disease-producing bacteria (known as _pathogenic_), when established in the blood and tissues of the body, bring about important chemical changes, depending upon the species of bacteria, and also produce a particular form of disease. The production of certain diseases by the agency of bacteria has now been proved beyond all doubt. In yellow fever, erysipelas, diphtheria, typhoid fever, consumption and other diseases, the connection has been definitely established.

The evil results these germs of disease produce vary greatly in kind and severity. Thus the bacteria of Asiatic cholera and diphtheria may destroy life in a few hours, while those of consumption may take years to produce a fatal result. Again, the bacteria may attack some particular organ, or group of organs, and produce mostly local symptoms. Thus in a boil there is painful swelling due to the local effect of the bacteria, with slight general disturbance.

398. The Battle against Bacteria. When we reflect upon the terrible ravages made by infectious diseases, and all their attendant evils for these many years, we can the better appreciate the work done of late years by tireless scientists in their efforts to modify the activity of disease-producing bacteria. It is now possible to cultivate certain pathogenic bacteria, and by modifying the conditions under which they are grown, to destroy their violence.

In brief, science has taught us, within certain limitations, how to change the virulent germs of a few diseases into harmless microbes.

399. Alcoholic Fermentation and Bacteria. Men of the lowest, as well as of the highest, type of civilization have always known that when the sugary juice of any fruit is left to itself for a time, at a moderately warm temperature, a change takes place under certain conditions, and the result is a liquid which, when drank, produces a p.r.o.nounced effect upon the body. In brief, man has long known how to make for himself alcoholic beverages, by means of which he may become intoxicated with their poisonous ingredients.

Whether it is a degraded South Sea Islander making a crude intoxicant from a sugary plant, a j.a.panese preparing his favorite alcoholic beverage from the fermentation of rice by means of a fungus plant grown for the purpose, a farmer of this country making cider from fermenting apple juice, or a French expert manufacturing costly champagne by a complicated process, the outcome and the intent are one and the same. The essential thing is to produce an alcoholic beverage which will have a marked physiological effect. This effect is poisonous, and is due solely to the alcoholic ingredient, without which man would have little or no use for the otherwise harmless liquid.

While the practical process of making some form of alcoholic beverage has been understood for these many centuries, the real reason of this remarkable change in a wholesome fruit juice was not known until revealed by recent progress in chemistry, and by the use of the microscope. We know now that the change is due to fermentation, brought about from the influence, and by the action, of bacteria (sec. 125).

In other words, fermentation is the result of the growth of low form of vegetable life known as an organised ferment. The ferment, whether it be the commonly used brewer's yeast, or any other species of alcoholic ferment, has the power to decompose or break down a large part of the sugar present in the liquid into alcohol, which remains as a poison, and _carbon dioxid_, which escapes more or less completely.

Thus man, ever p.r.o.ne to do evil, was once obliged, in his ignorance, to make his alcoholic drinks in the crudest manner; but now he has forced into his service the latest discoveries in science, more especially in bacteriology, that he may manufacture more scientifically and more economically alcoholic beverages of all sorts and kinds, and distribute them broadcast all over G.o.d's earth for the physical and moral ruin of the people.

Disinfectants.

400. Disinfectants, Antiseptics, and Deodorants. The word disinfectant is synonymous with the term _bactericide_ or _germicide_. A disinfectant is a substance which destroys infectious material. An antiseptic is an agent which may hinder the growth, but does not destroy the vitality, of bacteria. A deodorant is not necessarily a disinfectant, or even an antiseptic, but refers to a substance that destroys or masks offensive odors.

401. Air and Water as Disinfectants. Nature has provided for our protection two most efficient means of disinfection,--pure air (sec.

218) and pure water (sec. 119). The air of crowded rooms contains large quant.i.ties of bacteria, whereas in pure air there are comparatively few, especially after rain, which carries them to the earth. Living micro-organisms have never been detected in breezes coming from the sea, but in those blowing out from the sh.o.r.e large numbers may be found.

In water tainted with organic matter putrefactive bacteria will flourish, whereas pure water is fatal to their existence. Surface water, because it comes from that part of the soil where bacteria are most active, and where there is most organic matter, generally contains great quant.i.ties of these organisms. In the deeper strata of the soil there is practically no decomposition of organic matter going on, hence, water taken from deep sources is comparatively free from bacteria. For this reason, deep well water is greatly to be preferred for drinking purposes to that from surface wells.

402. Disinfectants. It is evident that air and water are not always sufficient to secure disinfection, and this must be accomplished by other means. The destruction of infected material by fire is, of course, a sure but costly means of disinfection. Dry heat, steam, and boiling water are valuable disinfectants and do not injure most fabrics. These agents are generally used in combination with various chemical disinfectants.