Biological Discords (Pathology)
The Point of View
One of the chief concerns not only of medical practice and surgery but of daily life as well, is the repair of biological machinery that has gone wrong. Although the human machine, unlike any man-made device, has the marvelous ability to adjust the interaction of its parts and to take care of routine repairs without outside aid, there is one obvious difference between the biological and the mechanical apparatus. In the case of the human machine extra parts to replace those worn or injured, if false teeth and wooden legs are excepted, are not procurable.
Much of the success in medical practice depends upon the restorative power inherent in the patient without outside assistance, or even in spite of outside interference.
From time immemorial “medicine men” and quacks, with vendors of cure-alls and patent medicines, have thrived upon the ignorance, credulity, and fears of their victims, but there is another more reassuring side to the picture. From Hippocrates and iEsculapius down there have arisen medicine men of a different stripe who have unselfishly sought the truth about the whence and why of bodily ills, to the great advantage of mankind.
The scientific study of the causes underlying biological disharmonies, or disease, is the field of Aetiology, of comparatively recent origin. To succeed in such investigations it is necessary to know what it is that has gone wrong, and this is the concern of Pathology which forms the basis of every system of medicine worthy of consideration.
Pathology, or the study of the abnormal, goes hand in hand with Physiology, the science that deals with the normal activities of organisms. To understand the abnormal it is indispensable to first know the normal. Both physiology and pathology in turn depend upon a knowledge of Morphology, or the science of lorm and structure, since normal as well as abnormal function is referable to a structural basis.
Deviations from the Normal
The “normal” is the prevailing type. If house cats with few exceptions were of the tailless Manx variety, a cat with a tail would appear abnormal, just as the unusual condition of six-fingeredness in man is regarded as abnormal simply because most people have only five digits on each hand.
Deviations from the normal frequently turn out to be a handicap to their possessors. The very fact that normality is only another way of saying that success in some particular has been gained by a majority of individuals, implies that variations from the standard have been less successful.
Deviations, however, are not always unfortunate. Lefthandedness, for example, is exceptional but it is not necessarily a handicap. Deviations from the normal that do handicap the possessor may take the form of deformities, misplacements, or disturbances, external as well as internal, that work ill to the organism. Disease, which is the particular province of pathology, may be broadly defined as any departure from the normal standard of structure or function of a tissue or organ.
There are at least three elementary activities of organisms, namely, (1) formative, that result in the growth and establishment of structural parts; (2) metabolic, having to do with the maintenance of the organism; and (3) responsive, which concern the interplay between the organism and the stimuli affecting it. Under normal conditions there is an optimum relation in each of these three lines of activity. An injury or disease may upset this optimum balance of health and well-being and cause either a cessation of these activities (death), or a quantitative or qualitative modification of one or all of them.
For centuries man’s greatest obstacle to advancement has been disease. It has turned back armies and caused the downfall of empires.
In 1792 the battalions of Prussia were halted in their attack upon the French revolutionary forces by an epidemic of dysentery. Disease decimated Napoleon’s horde of 500,000 soldiers, reducing their number to 3000 survivors during his march on Moscow. It was disease that reduced the crusaders from 300,000 to 20,000 in three years around 1100 A.D., while Haiti was lost to France in 1803 because yellow fever killed all but 3000 of the 25,000 soldiers sent by Napoleon to subdue the natives.
The construction of the Panama Canal was prevented until American engineers destroyed the breeding grounds of the mosquito that transmits yellow fever. Smallpox killed more than 60,000,000 people in Europe during the 18th century and maimed many others. In Mexico, where this scourge was introduced by the Spanish, 3,000,000 Indians succumbed to it, so that the conquest of Mexico by Cortez was due to disease rather than arms. Records show that at the time of the First World War more than 150.000 soldiers and prisoners died of typhus fever during the first six months. In 1664, bubonic plague claimed 24,000 out of a population of 200.000 in Amsterdam alone.
The spectacular statistics of epidemics are hardly more appalling than the daily occurrence of preventable deaths and disabilities, happening on all sides of us, to which we have become accustomed. Future generations should be educated to appreciate the valiant attack of pathologists who seek to lessen these disasters and to alleviate human suffering and to forestall the sacrifice of lives.
Disturbances that Work Ill
Disturbances that work ill to an organism by upsetting the optimum balance may be internal or external in their origin, although it is not always easy to determine to which of the two categories a particular case belongs.
Although an outline analysis might be carried to much greater length, only four kinds of probable internal disturbances are here mentioned, namely, (1) formative disturbances; (2) mechanical interferences; (3) responsive maladjustments; and (4) hereditary handicaps.
Formative Disturbances. When the complicated activities of growth and differentiation, to which attention was called in Chapter VIII, are passed in review, one wonders that so few structural mistakes or accidents actually occur.
The successful outcome of all embryonic development depends constantly upon the precise timing and infallible performance of each step, because every change and advance is conditioned upon what precedes and surrounds it. In the orchestra of developing parts a group of cells or an organ that is out of rhythm, like a blundering kettle-drummer, may throw all the other performers into confusion and change a symphony into discord.
The malformations and disharmonies which result from disharmony in growth and differentiation are termed terata, and the somber science concerned with such morphological misfits is called Teratology.
Terata may involve the entire individual, as in the case of “Siamese twins” of various kinds, or affect only parts of individuals or organs, as in such deformities as club foot, cleft palate, or hunchback. Other abnormalities may be simply groups of cells, like tumors, that have somehow lost step with the advancing host of correlating parts, and so fallen into disharmony. Tumors of this nature are uncoordinated members of the cellular state, and are termed benign or malign, according to the degree and manner in which they encroach upon or injure surrounding tissues. Malign tumors, like “cancers,” constitute one of the most disastrous disharmonies to which mankind is subject. Much study and exhaustive research is being directed towards the understanding and control of these troublesome formative disturbances.
Under the heading of formative disturbances there should also be included modifications in growth, which are evidently associated with something wrong in the behavior of certain regulatory endocrine glands, as for example, dwarfism and giantism.
Mechanical Interferences. Obstructional disturbances in the nutritional mechanism or the excretory apparatus may also work ill to an organism. The circulatory system, for example, through which the individual needs of the cellular structures are supplied, may suffer from local obstructions, blood deficiency, or interference with nerve supply. When for any considerable time a part of the body is deprived of blood by hemorrhage, or by such local obstructions as may result from congestion, pressure, wounds, or blood clots, a nutritive unbalance results. If the siege is not raised eventually, local starvation and death of the isolated tissues is the outcome, or, following exposure to ubiquitous putrefactive organisms, gangrene may set in with serious consequences to the neighboring living tissues. If there is protection from such foreign invasion, and the dead tissues are not too extensive, they finally become absorbed or are sloughed off, and normal conditions are restored.
Interruptions of the stimulative service from the nerve supply, by paralysis, shock, or any other interference, are also the immediate cause of a myriad of nutritional woes.
Responsive Maladjustments. By responsive maladjustments are meant such functional disturbances as follow in the wake of internal disharmonies of one kind or another that interfere with physical performance. The response to overwork, for example, may cause an increase in the number of the component cells in an organ and result in hypertrophy, or excessive growth. If this response is called forth to meet a normal physiological emergency, as in the hypertrophy of the mammary glands during lactation, or of the uterus in pregnancy, then it is normal and lies outside the field of pathology, but if it works ill to its possessor, like hypertrophy of the heart valves or the walls of the so-called “athlete’s heart,” then it becomes pathological.
Atrophy, either degeneration or arrest of growth, is an instance of nutritive disturbance that causes irregularity in the responsive activities. It usually follows a cessation of function, as when the optic nerve atrophies after the loss of an eye, or when a paralyzed leg or arm wastes away.
Hereditary Handicaps. Deviations from the normal that lead to disease may be of two kinds. First, they may be acquired in a great variety of ways during the lifetime of the individual; or second, they may be germinal, that is, inherited from ancestral streams of germplasm. Blindness, for example, may be acquired by accident any time before or after birth, or it may be germinal, as in the case of certain types of “congenital” cataract that “run in the family” and are inborn.
In the miscellaneous collection of germinal heirlooms that constitute our heritage there are bound to be some things that we wish we did not have. Every person in this imperfect world has at least one such hereditary “skeleton in the closet.” Frequently the skeleton cannot be suppressed and kept concealed in a closet, but must be painfully carried about in plain sight, like the burden on the back of Bunyan’s immortal pilgrim.
Diseases as such, particularly bacterial diseases, do not cross over the tenuous bridge of germ cells that connects one generation biologically with another. Constitutions and tendencies, however, that insure the eventual sequence of disease, are a part of the hereditary equipment of everyone.
The philosophy of the comparative anatomist and the pathologist consists in recognizing the fact that the most successful life does not depend upon anatomical and physiological perfection, but in making the best of imperfections.
Many of the causes of disturbance that put the “pathos” into pathology have their origin outside of the individual in the form of various environmental factors, of which those described as (1) thermal; (2) chemical; (3) barometric; (4) mechanical; and (5) biological, are representative.
Thermal Factors. Extreme variations from the normal limits of temperature to which an organism has become adapted may result in thermal disturbances that work ill. Here belong the disastrous effects of scalds, burns, and sunstrokes at one extreme, and frostbite and freezing at the other. The harm done in these disturbances may take the form of nervous shock, hemorrhage, or necrosis of the part involved, with subsequent invasion and infection by destructive bactcria.
Chemical Factors. Injurious chemical contacts, as in the case of ptomaines and various poisons introduced into the digestive tube and the blood, cause a variety of troubles. Painters and lead-workers frequently suffer from lead poisoning. The consequences of handling phosphorus or other deleterious chemical substances are also particularly unfortunate for those who are continually engaged in their use.
Barometric Factors. Deep-sea divers, mountain climbers, and aviators, who depart from the barometric environment to which they are normally attuned, harvest a crop of pathological protests as a result. Men in deep mines, or those engaged in tunnel construction who are forced to work for hours under abnormal atmospheric pressure, may acquire “caisson disease,” which manifests itself in paralysis of the legs, profuse bleeding from the nose, ears, and mouth, or even in apoplexy.
Mechanical Factors. Outside mechanical agencies may bring about sudden injuries of varying degrees of seriousness from mere scratches to extensive wounds that include the destruction of so much of the body as to imperil life itself. The power to repair such damage varies greatly in young and old. Comparatively undifferentiated tissues exhibit greater recuperative power than those that have attained considerable differentiation. The response of the body in repairing wounds, involving as it does the behavior of the cellular units concerned, is of particular interest to the pathologist.
Sometimes mechanical factors instead of resulting in sudden wounds, may take the form of irritants that work more slowly and insidiously. Cancer of the lip, for instance, is said to be more frequent in the case of pipe-smokers, who have subjected themselves for a considerable time to local mechanical irritation of a pipestem, than among non-smokers.
Many occupations that involve inhaling irritating dust particles, like handling coal, threshing grain, cutting stone, and polishing metals with abrasives, induce manifestation of diseases as a consequence of mechanical irritants acting upon the respiratory surfaces.
Biological Factors. There are three general kinds of parasites that may attack other organisms and upset their normal course of living. They are (1) pathogenic bacteria; (2) pathogenic protozoans; and (3) a heterogeneous group of larger parasites, including certain worms, insects, fungi, and other harassing forms that prey upon their betters.
Pathogenic bacteria are microscopic plants that cause such diseases as tuberculosis, cholera, tetanus, anthrax, and typhoid fever. The harm they do is usually the result of toxins, or poisons, which they set free in the tissues of their hosts during the course of their own metabolic processes, or when they die. They may, however, by sheer force of numbers resulting from their prodigious powers of multiplication, either plug up the capillaries in which they swarm so that the circulation of blood is impeded or prevented, as in anthrax, or they may induce the formation of a bulky mass that acts as a strangling gag upon their victim, as in diphtheria, or “membranous croup,” as it was formerly called.
Beginning with Pasteur and Lister within the memory of people now living, the science of Bacteriology, which has to do with these minute foes of mankind, has so increased in importance and achievement that it has become indispensable in all modern medicine and surgery. Without doubt the future will see still greater triumphs and conquests in this fertile field of human endeavor.
The science of Protozoology, with its wide application to the control of diseases induced by pathogenic one-celled animals, has lagged somewhat behind the twin science of bacteriology, partly because the technic involved in obtaining pure cultures of organisms for accurate experimentation is more difficult. Nevertheless much has been learned already and greater discoveries and successes in this field surely await the investigator just around the corner.
Many diseases are connected with protozoan parasites which infest the blood of their hosts, particularly in the tropics, such as malaria and African sleeping sickness, while the troubles following in the train of amoebic dysentery are an example of the consequences caused by protozoan highwaymen that infest the digestive tract.
Parasitology in general, out of which the flourishing young sciences of bacteriology and pathogenic protozoology have sprung, is now usually associated with larger parasites, like tapeworms, flukes, hookworms, and other worms, that take up their domicile in the bodies of their hosts, or such external visitors as ticks, lice and fleas, which Mark Twain said keep a dog from “thinking about being a dog.”
Sources of Pathological Knowledge
A knowledge of the facts of pathology, that is daily contributing so much to the alleviation of abnormal conditions, is gained principally through clinics, autopsies, physiological and micropathological research, comparative pathology, and animal experimentation.
Clinics include bedside experiences gained by actual observation of the abnormal conditions exhibited by the patient.
Autopsies are post-mortem examinations in order to find out what has gone wrong with the machinery of biological clocks that have stopped.
Micropathological research is directed towards an intimate understanding of the behavior and appearance of cellular units under abnormal conditions. It includes not only Pathological Histology, but also Bacteriology and Pathological Protozoology.
Comparative Pathology, also with human pathology as an objective, gains added facts by the indirect method of approach through other members of the animal kingdom. Man is too complex a mechanism to be understood at once without some preliminary acquaintance with simpler mechanisms of animal life. Moreover, pathology in general is much more than the science of human ills. It is a field of study fertile enough to promise rewards to the student of pure science whose eyes are not necessarily fixed upon immediate utility to man.
Animal experimentation has made possible not only a knowledge of the facts and principles of pathology, but has also cleared the way for the diagnosis and control of the pathological disharmonies that beset mankind. Without recourse to animal experimentation the triumphs of modern medicine could never have come about.
It is unfortunate that the word “vivisection” in this connection has become such a bogey, for it has caused many people to remain uninformed or misinformed about a very important matter. The truth is well stated by Dr. W. W. Keen in a pamphlet entitled, What Vivisection Has Done for Humanity published in 1910, the concluding paragraphs of which are here quoted:
“The alleged atrocities so vividly described in antivivisection literature are fine instances of ‘yellow journalism,’ and the quotations from medical men are often misleading. Thus, Sir Frederick Treves, the eminent English surgeon, is quoted as an opponent of vivisection in general. In spite of a denial published seven years ago the quotation still does frequent duty. I know personally and intimately Horsley, Ferrier, Carrel, Flexner, Crile, Cushing, and others, and I do not know men who are kinder or more lovable. That they would be guilty of deliberate cruelty I would no more believe than that my own brother would have been.
Moreover, I have seen their experiments, and can vouch personally for the fact that they give to these animals exactly the same care that I do to a human being. Were it otherwise their experiments would fail and utterly discredit them. Whenever an operation would be painful, an anesthetic is always given. This is dictated not only by humanity, but by two other valid considerations: first, long and delicate operations cannot be done properly on a struggling, fighting animal any more than they could be done on a struggling, fighting human being, and so again their experiments would be failures; and second, should any one try an experiment without giving ether he would soon discover that dogs have teeth and cats have claws.
Moreover, it will surprise many of my readers to learn that of the total number of experiments done in one year in England 97 per cent were hypodermic injections and only 3 per cent could be called painful!
If anyone will read the report of the recent British Royal Commission on Vivisection he would find, says Lord Cromer, ‘that there was not a single case of extreme and unnecessary cruelty brought forward by the Antivivisection Society which did not hopelessly break down under cross examination.’
In view of what I have written above and many times as much could be added - is it any wonder that I believe it to be a common-sense, a scientific, a moral, and a Christian duty to promote experimental research? To hinder it, and, still more to stop it would be a crime against the human race itself, and also against animals, which have benefited almost as much as man from these experiments.
What do our antivivisection friends propose as a substitute? Nothing except clinical that is, bedside and post-mortem observations. These have been in use for two thousand years and have not given us results to be compared for a moment with the results gained by experimental research in the last fifty, or even the last twenty-five years.
Finally, compare what the friends and foes of research have done within my own professional lifetime. The friends of research have given us antiseptic surgery and its wonderful results in every region and organ of the body; have abolished, or nearly abolished, lockjaw, blood poisoning, erysipelas, hydrophobia, yellow fever; have taught us how to make maternity almost absolutely safe; how to reduce the mortality of diphtheria and cerebrospinal meningitis to one-fourth and one-third of their former death-rate, and have saved thousands of the lower animals from their own special diseases.
What have the foes of research done for humanity? Held meetings, called the friends of research many hard names and spread many false and misleading statements. Not one disease has been abolished, not one has had its mortality lessened, not a single human life has been saved by anything they have done. On the contrary, had they had their way, puerperal fever and other hideous diseases named above, and many others, would still be stalking through the world, slaying young and old, right and left and the antivivisectionists would rightly be charged with this cruel result.”
The Control of Disease
In earlier days of human ignorance, disease was regarded as due to the presence of evil spirits, and cures were supposed to be effected when these malign visitors were properly exorcised by some conjurer or medicine man. Although the conjurer in various guises still trades upon superstition and ignorance, the modern controller of disease has come to recognize that all methods of healing, almost without exception, resolve themselves simply into extensions of the natural phenomena of growth and repair that are inherent in the patient. For example, it has been found that by injecting dead cultures of the causal agents into subjects infected by a pathogenic organism, there is produced in the body fluids a substance (opsonin) which apparently in favorable conditions unites with the living causal pathogenic bacteria and so sensitizes them that they are readily taken up and destroyed by the phagocytic cells of the blood. The afflicted body, therefore, cures itself whenever a cure is effected, and frequently nearly all that the modern medicine man can do is to direct intelligently the efforts of the body in its task of restoring normal conditions.
Three general directions are followed in modern attempts to control disease, namely, by curative, preventive, and creative medicine.
Curative medicine, finding itself in a world of disease and disaster, sets out to heal the sick and bind up the wounds of the injured. It has assumed a colossal task and, like the Good Samaritan that it is, has gone about the business with noble devotion and increasing success.
Preventive medicine, on the other hand, seeks to forestall trouble. Diseases like smallpox are prevented by vaccination, while by means of antitoxins the poison of invading germs, like that in diphtheria, is counterbalanced and rendered innocuous. Protective immunity against disease is thus accomplished by using vaccines, antitoxins, opsonins, endocrine extracts, and other resources of the bacteriologist and physiological chemist.
Creative medicine, which at present is hardly more than a dream for the future, takes a long look ahead and attempts to prevent the abnormal with all its disastrous chain of consequences, by seeing to it that, so far as possible, only the normal are born into the world. This is the hopeful field of Eugenics, which seeks to lessen and prevent disease by providing an hereditary equipment that is able to maintain itself triumphantly harmonious in the face of besetting discords.
All of these lines of possible betterment must advance through the frontier of pathology, hence the importance of this field of biology.