Physical exploration and diagnosis of diseases affecting the respiratory organs

Front matter

o.

0^ '^'^^ ''

,.4

Preface

The great importance of physical exploration in cases of thoracic disease is now generally admitted. "While its scope of application, the significance of certain of its phenomena, and more especially the mode of their production, furnish occasions for discussion and differences of opinion, few intelligent physicians, at the present day, refuse to acknowledge that the discovery of Laennec forms a memorahle epoch in the history of medicine ; nor will the claims of this branch of our art on the attention of the medical practitioner be denied by any who are qualified to place a proper estimate upon its value. But although these positions are indisputable, the number who give much attention to the principles and practice of physical exploration is quite small, its advantages being practically rejected by a large proportion of the medical profession. May not this be in a measure due to the paucity of works treating of the subject specially, and with a degree of fulness commensurate with its importance ? This inquiry, mainly, has led to the preparation of this volume. The founder of auscultation succeeded in bringing the diagnosis of diseases affecting the pulmonary organs to an astonishing degree of precision. Yet the labors of those who have followed in the footsteps of their illustrious master, have done much for the improvement and extension of physical exploration ; so that the great work of Laennec, remaining as it ever will a splendid monument of his genius and industry, is no longer adequate to a complete exposition of our existing knowledge. The few special treatises which have more recently appeared, are mostly designed as manuals for the medical student. The most comprehensive

VI PREFACE.

work published in our language witMn late years is tbe admirable treatise by Prof. Walsbe. In this work, which includes diseases of the heart and aorta, embracing also the morbid anatomy and treatment, as well as the diagnosis, the consideration of physical signs is necessarily condensed. My aim has been to supply what appears to me a desideratum, viz., a work limited to diseases affecting the respiratory organs, treating in extenso, and almost exclusively, of the principles and practice of physical exploration as applied to the diagnosis of these affections. So much, briefly, for the motives and objects which have prompted the undertaking.

In preparing the volume now submitted to the profession, my plan has been to treat of the physical signs as regards their individual and differential characters, their significance and diagnostic relations, separately and combined, without imposing on myself restraint on the score of brevity. "Whilst I have desired not to be either tediously minute or diffuse, I have intentionally amplified, somewhat after the usual m.ode of oral teaching, under the belief that this course would best subserve the interests of the reader, and that the importance of the subject renders no apology necessary for the size of the book.

I have striven to make the work as practical as possible ; and, therefore, the various topics are considered with almost exclusive reference to their direct clinical bearings. Very little attention is devoted to theoretical questions. To the mechanism of physical phenomena relatively small space is accorded, recognizing as the only safe basis of our knowledge of their significance and pathological relations, clinical facts taken in connection with morbid anatomy, and believing that a priori deductions from the laws of physics, or analogical inferences from experiments made out of the body, and even with the dead subject, are to be received with great circumspection. The recapitulation in different pathological connections of the distinctive characters of the different signs, which, as the reader will notice, is a feature of the work, has not arisen from inadvertency ; for, whereas, perfect familiarity with these characters is indispensable to skill or success in the practice of exploration, they are to be fixed in the memory by means of repetition, on the principle which underlies the oral system of

PREFACE. Vll

acquiring a foreign tongue. The motto, " repetition sans cesse^'' adopted by an author of French exercises constructed after this system/ is well suited for the student or practitioner who is ambitious to excel in physical exploration.

Whoever undertakes to write a didactic treatise, in effect, assumes that he is competent to the task. It is not, therefore, unbecoming for me to state that during several years devoted to clinical pursuits, the physical exploration of the chest has occupied a considerable share of my attention. Of most of the practical points embraced in this work, I am able to speak from experience. With respect to certain signs, the views which I have been led to form from personal observation are original. I may particularize here, the characters of pitch distinguishing the respiratory sound commonly called rude or rough, and which give to a prolonged expiration its significance as a sign of increased density of lung from tuberculous or other solid deposit ; also, the relative pitch of the inspiratory and expiratory sounds in the cavernous, as contrasted with the bronchial, respiration. Other points, not dwelt upon by writers on this subject, which I may mention in this place, are the importance of determining the line of the interlobar fissure, as a means of distinguishing between the percussion-dulness of lobar pneumonitis and liquid effusion, and the clinical value of the souffle or bellows' sound, accompanying the act of whispering, as a sign of solidification. In the perusal of the work, the reader will perceive that occasionally the results of my own observation do not altogether accord with the opinions of others. Under these circumstances, I do not hesitate to follow a rule which, as it seems to me, in matters purely of observation, should not lead to the imputation either of egotism or presumption, viz., not to be more ready to distrust one's own accuracy than that of others. Were an opposite course to be required, there would be small encouragement for original research. While engaged in WTiting the work, I have been forcibly impressed with the need of farther analytical investigation of carefully recorded data. Questions have so frequently arisen which are to be settled only by an appeal to the results of observation, that I have sometimes been tempted to lay aside the pen, and have resumed it only under the con-

1 Manesca.

VUl PftFf ACBL

viclion that sach qnestions mnst^ for a long period, contmue to arise ; and that to wait for Uie means of meeting promptly every inquiry, is equivalent to an indefinite postponement- This field of research, like every other in the extensive domain of liledieal science, offers scope for unlimited improvement; and it is to be expected that continued efforts in its cultivation will develope additional resources^ rendering it more and more valuable.

Endeavoring, as £ir as practicable, to exhibit the actual state of our present knowledge of the physical diagnosis of diseases of the respiratoiy organs, I have availed m^yself of the latest and most approved works on the subject. My acknowledgments are especially due to the Practical Treatise on the Diseases of the Lungs, Heart,* and Aorta, by Professor Walshe, and to the Traits Pratique d'Auscultation, etc., by MM. Barth and Koger.^ I have also consulted with advantage, the wori^ of Stokes, Foumet, Gerhard, C. J. B. Williams, Hughes, Bowditcb, Swett, Alfred Stille, Holmes, J. Hughes Bennett, and Skoda. In addition, numerous papers on particular topics have been examined, as well as books treating incidentally of matters pertaining to physical exploration, which are referred to in the body of the work.

One of the authors just named has enuncifi-ei views, which, fi»m their novelty and boldness, have attracted considerable attention. I refer to Professor Skoda, of Yienna. The theory of consonance, by which this author attempts to explain some of the most important of the physical signs, and upon which he bases certain practical conclusions, appears to me very fer from being satisfiictorily established. In his clasafication and designation of physical signs, I am unable to perceive that aught is gained in clearness or simplicity. Some of his assertions pertaining to matters of simple observation, involve a denial of the positive results of the experience not of one, but of nearly all observers — ^for example, that the crepitant rale, as described by liaennec, is rarely heard in pneumonitis, and that the percussion-resonance is not affected by the presence of isolated tubercles in a very considerable quantity, unless accompanied by an altered condition of the interstitial tissue. Moreover, the pervading tone of ihe work tends to create in the mind of the

' The editioDs c^bodi diese worts fiw 1834. are referred la

PREFACE. IX

student a scepticism witli respect to the value of physical exploration, which is at variance with the confidence of other observers not less experienced than himself. In venturing upon these critical remarks, I am alone actuated by a desire that the importance of the subj ect should not be undervalued. Frequent occasions for reference to the valuable contributions of Professor Skoda will appear in the following pages.

In order that physical exploration shall be available in the hands of practitioners who have neither time nor inclination to devote to it special attention, to the prejudice of attainments in other branches of medical knowledge, as much simplicity in its principles and practice as comports with a due regard to its usefulness, is to be desired. ITeedless distinctions and over refinements are to be deprecated. Mutations in classification and nomenclature are as much as possible to be avoided. With these views, I have refrained from suggesting additions or changes, which, should they even be considered improvements, might occasion complexity and confusion ; and I have passed over some points which, from their dubious or unimportant character, seemed likely to prOve a source of embarrassment, rather than an advantage to the student. The only innovations I have ventured to propose are the substitution of a new name for rude or rough respiration, viz., broncho-vesicidar, and the use of the terms vesiculo-tympanitic resonance, applied to a percussion-sound combining the tympanitic and vesicular qualities, and broncho-cavernous respiration, denoting a mixture of the cavernous and bronchial modifications of the respiratory sound.

In conclusion, I embrace this opportunity to express acknowledgments to my friend. Professor Alfred Stills, for kindly consenting to read the proofs of the work as it has passed through the press. While I have no right to hold him responsible for any of its defects, I am truly grateful to him for many valuable suggestions.

University of Louisville, Ky.

February, 1856.

CONTENTS, ii^troductio:n\

SECTION I. Preliminary Points pertaining to the Anatomy and Physiology of

THE Respiratory Apparatus, . . . . .17

1. Thoracic Parietes, . . . . . . 17

2. Pulmonary Organs, . . . . . .34

3. Trachea, Bronchi, and Larynx, .... 46

SECTION II. Topographical Divisions of the Chest, .... 54

1. Anterior Regions, . . . . . . .56

2. Posterior Regions, ...... 60

3. Lateral Regions, . . . . . . .61

CHAPTER I. Definitions — Different Methods of Exploration — General Remarks, 6o

CHAPTER 11.

I. Percussion in Health, ...... 78

a. Post-Clavicular Region, . . . . .80

b. Clavicular Region, . . . . . 81

c. Infra-Clavicular Region, . . . . .81

d. Scapular Region, ...... 83

Xll

Contents

e. Inter-Scapular Region,

f. Mammary Region,

g. Infra-Mammary Region, . . h. Sternal Region,

CHAPTER III. Auscultation

I. Auscultation in Health, .....

a. Phenomena incident to Respiration, .

1. Tracheal Respiration, ....

2. Bronchial Respiration, ....

3. Vesicular Respiration, ....

b. Phenomena incident to the Voice,

1. Tracheal Voice, .....

2. Bronchial Voice, .....

3. Normal Vesicular Vocal Resonance,

c. Brief Summary of Facts, ....

d. Phenomena incident to the act of Coughing, II. Auscultation in Disease, .....

a. Phenomena incident to Respiration,

1. Modified Respiratory Sounds,

a. Increased Intensity of the Vesicular Murmur —

Exaggerated Respiration, .

b. Diminished Intensity of the Vesicular Murmur —

Feeble or Weak Respiration, Suppressed Respiration, ' .

Bronchial Respiration, Broncho-Vesicular or Rude Respiration, Cavernous Respiration,

Tabular View of the Distinctive Characters pertaining to the Different Abnormal Modifications in Quality, Pitch, etc., of Respiratory Sounds, h. Shortened Inspiration,

i. Prolonged Expiration, .... k. Interrupted Respiration,

2. Adventitious Respiratory Sounds or Rales, .

a. Table showing the Number, Names, and Anatom cal Situations of the Pulmonary Rales,

b. Sibilant Rale, ....

180 185 187 197 202

209 210 211 214 216

219 220

CONTENTS.

Xlll c. Sonorous Rale, ....

d. Mucous Rales, ....

e. Sub-crepitant Rale, ....

f. Crepitant Rale, ....

g. Cavernous Rale or Gurgling, h. Indeterminate Rales, i. Table Exhibiting tlie Distinctive Characters and

Diagnostic Indications of the Different Rales, j. Attrition or Pleural Friction Sounds,

b. Phenomena Incident to the Voice,

1. Exaggerated Vocal Resonance and Bronchophony,

2. Diminished and Suppressed Vocal Resonance,

3. Cavernous and Amphoric Voice, Pectoriloquy, .

4. iEgophony, .....

5. Summary of Facts pertaining to Vocal Signs.

c. Phenomena incident to the Act of Coughing,

1. Bronchial Cough, ....

2. Cavernous Cough, ....

d. Metallic Tinkling, .....

e. Abnormal Transmission of the Sounds of the Heart, History, ......

Chapter VII. 221 223 226 229 235 237

295 297 304 308 311

312 312

317 320 322

323 329 329

330 332 332

XIV

CONTEXTS.

CHAPTER Vni.

ReCAPITULATOET ExUMERATIOy OF THE PHYSICAL SlGXS FURNISHED BY

THE Several Methods of Exploratiox, .... 333

CHAPTER LK.

CORRELATIOX OF PHYSICAL SiGXS, ....

1. Signs Correlative to those furnislied by Percussion,

2. Signs Correlative to those furnished by Auscultation,

336 338 342

PAET 11.

Diagnosis of Diseases Affegtixg the Respiratory Organs, 351

Chapter I

Broxchitis, Pulmoxary or Broxchial Catarrh, c. Summary of Physical Signs belonging to Acute Ordinary Bronchitis, ....

2. Capillary Bronchitis,

a. Physical Signs and Diagnosis,

b. Summary of Physical Signs, .

3. Pseudo-Membranous or Plastic Bronchitis,

a. Physical Signs and Diagnosis,

b. Summary of Physical Signs,

5. Secondary Bronchitis,

6. Bronchial or Pulmonary Catarrh,

CHAPTER n.

DlLATATIOX AXD COXTRACTIOX OF THE BrOXCHIAL TuBES — PeRTUSSIS a. Physical Signs, ......

b. Diagnosis, .......

c. Summary of the more important of the Diagnostic Characters, .......

2. Contraction of the Bronchial Tubes, ....

352 353 353 357

380 380 383 385

391 391

CONTENTS.

XV

3. Pertussis — Hooping Cough, ....

Physical Signs and Diagnosis, a. Physical Signs, .....

b. Diagnosis, ......

Chapter III

Pneumonitis — Imperfect Expansion (Atelectasis) and Collapse, a. Physical Signs, .....

b. Diagnosis, ......

c. Summary of Physical Signs, ....

a. Physical Signs and Diagnosis, .3. Chronic Pneumonitis, .....

395 395 397 397 398 400

CHAPTER ly.

Emphysema,

2. Interlobular Emphysema,

443 443 444 452 455 455

CHAPTER y.

Pulmonary Tuberculosis — Bronchial Phthisis, . . . 458

Acute Phthisis, . . . . . . .503

Retrospective Diagnosis of Tuberculosis, . . . 506

Tuberculosis of the Bronchial Glands — Bronchial Phthisis, . 509

CHAPTE

R yi.

MO

NARY OEdema — Gangrene of the

Lungs — Pulmonary Apoplexy

— Cancer of the Lungs — Cancer in the Mediastinum,

L

Pulmonary OEdema,

.

b. Diagnosis, .

Gangrene of the Lungs,

Pulmonary Apoplexy, .

XVI

CONTENTS.

CHAPTER YII.

Acute Pletjritis — Chroxic Pleuritis — Empyema — Htdrothorax— Pneumothorax — Pxeumo-Hydrothorax — Pleuralgia — Dia phragmatic Herxia, c. Retrospective Diagnosis,

d. Summary of Physical Signs,

3. Empyema, .

4. Hydrothorax,

5. Pneumothorax,

6. Pneumo-Hydrothorax. .

b. Diagnosis, 0. Summary of Physical Signs,

7. Pleuralgia,

8. Diaphragmatic Hernia,

CHAPTER VIII.

Diseases Affectixg the Trachea axd Lartxx — Foreigx Bodies ix THE Air-Passages,

1. Auscultation of the Trachea and Larynx,

2. Examination of the Chest, a. Summary of Physical Signs, .

Appendix

Ox THE Pitch of the Whisperixg Souffle oyer Pulmoxary Exca

PHYSICAL EXPLOEATION.

Introduction

SECTION I.

PRELIMINARY POINTS PERTAINING TO THE ANATOMY AND PHYSIOLOGY OF THE RESPIRATORY APPARATUS.

The study of diseases affecting the respiratory apparatus involves, as a point of departure, acquaintance with the several structures, organs, and functions which this apparatus embraces. To this preparatory knowledge it is presumed, of course, the reader has already given more or less attention ; but it will be useful to review certain points pertaining to the anatomy and physiology of this portion of the organism, which will be found to have direct and intimate pathological relations. To these points this section will be mainly limited, omitting details other than those of special importance in their bearings on the subjects to be subsequently considered.

The respiratory apparatus comprises 1st, the thoracic parietes, inclusive of the diaphragm ; 2d, the pulmonary organs contained within the thoracic cavity ; 3d, the canal or tube leading from the lungs to the pharynx, consisting of the bronchi and their subdivisions, the trachea, and larynx. The throat, mouth, and nasal passages, although involved in respiration, are rather adjuncts of the respiratory apparatus than constituents of it, their construction having more direct reference to other functions.

I. The Thoracic Parietes.

The portion of the skeleton called the thorax is composed of the dorsal vertebrae, the ribs, and the bones of the sternum, forming by their union, together with their intervening cartilages, a truncated cone, designed to protect the organs which it contains, and to be subservient to certain movements concerned in respiration. The bony arches, the ribs, exclusive of the two last on each side (reckoning, as is usual, from the summit of the cone downward), are joined, either to the sternum, or to each other, bv cartilages to which the walls of the chest are in a great measure indebted for their elasticity and mobility. The superior seven ribs joined to the sternum are called the true ribs, and the remaining five on each side are distinguished as x}iQ false ribs. The two lowest on each side, from the fact that their anterior extremities are disconnected from those situated above them, as well as from each other, are known as the floating ribs. The elasticity of the costal cartilages is greatest in early life : it becomes impaii-ed, as a general rule, in proportion to age, and with advanced years may be nearly lost in consequence of ossification. Under these circumstances the alternate increase and diminution of the thoracic capacity with the two acts of respiration, so far as the successive expansion and contraction of the thoracic walls are therein involved, must of necessity be in some measure restrained.

The dii'ection of the first rib is nearly horizontal. The remainder have an oblique direction downward, the obliquity increasing with each inferior rib. Below the third rib the costal cartilages also have an oblique direction, but not corresponding to that of the ribs. From the point of theii' attachment to the ends of the ribs, they pursue an upward direction to their sternal connections. Hence a line coincident with the axis of these ribs, forms with a line passing through the axis of their cartilages, an angle which is more acute with each inferior rib. The length of the costal cartilages also increases successively with the three lowest of the true ribs. These anatomical points, viz., the oblique downward direction of the ribs, and the oblique upward direction of their cartilaginous prolongations, are provisions for the respu'atory movements, so far as these movements relate to the anterior and lateral portions of the chest. With the act of inspiration, more especially when its force is voluntarily augmented, the lateral and antero-posterior diameters are increased. This is effected chiefly by the elevation of the ribs, by which their obliquity is diminished, causing them to approximate and even attain to a horizontal direction, tending thus to bring the ribs and the costal cartilages on a continuous line, diminishing or abohshing the acute angle formed by the union of the ribs and cartilages. After the cessation of the motive power which effects these changes, in other words, with the act of expiratioiij the elasticity of the cartilages suffices to restore that relation to the ribs which is natiirally assumed. These movements are abnormally increased and diminished in consequence of different forms of disease. A change, also, as regards the oblique direction of the ribs is attendant on certain thoracic affections, viz., pleurisy with a large accumulation of liquid in the pleural sac ; the presence of liquid and gas in pneumo-hydrothorax, and in some instances of abnormally distended lung, constituting a form of emphysema. In connection with these affections the same changes are mechanically produced which are effected by a forcible act of inspiration, with the important difference, that while the enlargement of the chest in the latter case is but for an instant, in the former case it persists so long as the morbid conditions which have induced it continue.

The margins of the- ribs are not in contact, but separated, leaving what are termed the intercostal spaces. In consequence of the progressively increasing obliquity in the direction of the ribs the intercostal spaces are broader in front than behind. Under different morbid conditions these spaces are increased and diminished in width. The former is incident to the accumulation of a large quantity of liquid in the chest, the latter to contraction of the chest following the removal of this liquid by absorption or otherwise. In the female skeleton the upper ribs are more widely separated than in the male, and they possess also, relatively, a greater degree of mobility. This anatomical difference in the two sexes has relation to the greater part which the summit of the chest takes in the respiratory movements in the female.

The intercostal spaces when the thorax is invested with the soft parts, are filled with muscular substance, which constitute a portion of the active agents employed in carrying on the respiratory movements. These intervening muscular layers are depressed below the level of the ribs, causing furrows, which are called the intercostal depressions. In persons with small or moderate adipose deposit, these depressions are plainly indicated on the surface, being observable especially in front and laterally, at the lower part of the chest. They are everywhere visible, except in the portions covered by the scapula, in cases of great emaciation. A change as respects this anatomical point occurs in certain diseases, viz., when there is an accumulation of a large quantity of liquid ; and sometimes when the chest is dilated by over-distended lung in emphysema. Under these

20 ANATOMY AX D PHYSIOLOGY.

circumstances, especially with the former condition, the intercostal depressions are abolished, and the interrening integument may even project beyond the level of the ribs when a very large quantity of liquid is contained in the pleural sac.

The scapula and clavicle, with the soft parts, give to the thorax a shape quite different from that which it presents divested of these appendages. Compared to a truncated cone, the base is now above. These superadded bones, certain muscles investing portions of the thoracic walls, and, in the female, the mammary gland, offer obstacles in the way of exploring the chest for the physical signs of disease which will be noticed hereafter in connection with the consideration of these signs.

The partition wall separating the chest from the abdomen is the tendino-musctJar septum, the diaphragm, springing from the lumbar vertebrae, from the first to the fourth inclusive, and attached to the six inferior ribs. Examined from below it forms a vaulted or arched roof of the abdominal cavity, its upper surface having a corresponding convexity extending into the thoracic cavity on each side. The height to which this convexity rises in the two sides is not equal, being greater in the right than in the left side. In the former it rises as high as the fourth intercostal space ; in the latter to a level with the fifth rib. Thus the right chest has a vertical diameter somewhat less than that of the left. Accumulation of liquid within the pleural sac, and dilatation of the lungs in some cases of emphysema, may cause, mechanically, depression of the diaphragmatic arch ; and, on the other hand, enlargement of the liver on the right side, and, on the left side, enlargement of the spleen, or distension of the stomach, will produce an elevation above the normal height.

The contraction of the muscular structure entering into the composition of the diaphragm diminishes its vaulted form, depressing it to a plane, thereby enlarging the vertical diameter of the thoracic space. In this way it becomes the most important agent in the act of inspiration, resuming its convexity with the act of expiration. These movements are liable to be restrained, or arrested by various affections, which will be presently mentioned.

Considered as divided into lateral halves, the thoracic parietes on the two sides, not only as respects the skeleton, but when invested with the soft parts, should be nearly symmetrical, so that any considerable deviations in this point of view, denote either present disease, or deformity. An exception relates to the semicircular

THE THORACIC PAKIETES. 21

measurement at the middle and inferior portion of the chest. The right side usually, but by no means invariably, measures somewhat more than the left, the average difference being about half an inch. Of 133 cases of persons in good health in which measurements were made by M. Woillez, the right semi-circumference exceeded the left in 97 ; the left exceeded the right in 9, and both sides were equal in 27. The greater size of the right side, as determined by measurement, is usually attributed to the presence of the liver on that side. The facts presented by the author just named, however, seem to show that it depends, in a measure at least, on the greater use of the right upper extremity, which is habitual with most persons. In no instance in which the persons were right-handed did the left exceed the right SIDE in measurement; on the other hand, of cases in which the persons were left-handed^ in three the left side exceeded the right, and in the remaining two cases both sides were equal. In a perfectly symmetrical chest the shoulders should be on the same level ; and in the male, the nipples situated on the fourth rib, or the foui'th intercostal space, should be on the same transverse line, and equidistant from the centre of the sternum. The general law of symmetry as regards correspondence in similar portions of the chest on the two sides, is of importance in determining the existence of intrathoracic diseases ; and, with reference to its application, it is to be borne in mind that certain past affections are liable to leave deviations more or less permanent. The most common cause of deformity is spinal curvature, which may be sufficient to disturb the symmetry of the two sides without existing to a degree to be noticed unless a careful comparison be instituted. Cases of slight lateral curvature depressing the shoulder and nipple of one side (oftener the right than the left side), approximating the margins of the ribs, and diminishing the semi-circumference, are very frequent, and liable, without special attention, to be overlooked. Certain diseases within the chest lead to marked alterations in the conformation on one side. This is true especially, as will be seen hereafter, of chronic pleurisy. The chest on one or both sides may be deformed in various ways irrespective of spinal curvature. Thus the sternum may project unnaturally, causing the ''chicken" or "pigeon breast," or on the contrary more or less depressed ; there may be flattening on one side produced perhaps by pressure from the arm of the nurse in early infancy ; contraction at the lower part of the chest in females, occasioned by tight lacing ; distortions from fractures or other injuries, etc. These

*2-2 A^'ATO^IY A>-D PHYSIOLOGY.

deviations from sjmmetrj are sufficiently obvious, and will not therefore escape notice. Practically, they are of great importance in determining the physical signs oi present disease. The greater portion of these signs, as "will be seen hereafter, being based on the assumption that, irrespective of present disease, the two sides of the chest are in unison, it becomes obviously an essential preliminary to determine, in individual cases, to what extent the law of symmetry is applicable. The researches by M. Woillez^ show that chests presenting in all particulars complete regularity of conformation are found in only the proportion of about twenty of every hxmdred persons. Deviations from symmetry, either disconnected from disease (physiological), or resulting from previous morbid conditions (pathological), therefore, exist to a greater or less extent, in a large proportion of individuals. This fact would impair very materially the value of physical exploration were it not practicable, as it generally is, to determine whether deviations which may be discovered are due to present disease, or existed previously.

The respiratory movements involve certain points important to be premised in addition to those already noticed.

A complete respiration, as is well known, comprises two acts, viz., an act of inspiration, and an act of expiration. In health, after adult age, the respirations are repeated from 14 to 20 times per minute, the habitual frequency varying considerably within healthy limits in different individuals. The frequency is somewhat greater in females than in males, and still greater in children. Deviations as regards the frequency of the respirations, exceeding the limits of health, are important symptoms of disease. In various affections compromising the function of hsematosis, the frequency of the respirations is considerably increased, rising for example in bronchitis affecting the smaller tubes, to 30, 40, 50, 60, or even a still greater number, per m in ute. On the other hand, an abnormal diminution in frequency accompanies certain morbid conditions of the nervous system affecting indirectly the respiration. Thus, the respirations are morbidly infrequent, or slow, in apoplexy, and coma, however induced. The immediate object of the act of inspiration is the enlargement of the thoracic space, the air rushing in to fill the vacuum

- " Rechercties pratiques sur rinapection et la mensxuation de la poitrine, considerees comme moyens diagnostiqaes complementaires de la percussion et de rauscultation." Paris. 1837. Archives Generales de 31edecine, Seme Serie, tome i, p. 73.

thus created within the air cells and tubes of the lungs. This enlargement is effected by means of muscles attached to the thoracic walls, on the one hand, and, on the other hand, by the depression of the diaphragm. The immediate object of expiration is to restore the chest to the dimensions it naturally assumes when not acted on by the dilating muscles, and to contract it sometimes beyond that point, thus causing expulsion of the air received by the act of inspiration. The simple restoration of the chest is due mainly to the elasticity of the dilated parts, but contraction beyond the dimensions which it naturally assumes, is eiFected by expiratory muscles. The movements incident to the two acts, respectively, in ordinary or tranquil respiration ; the modifications exhibited when the breathing is exaggerated or forced ; the normal differences to be observed in different persons ; the variations due to age, sex, etc., are physiological points, not only interesting in themselves, but of utility in order to appreciate the aberrations associated with diseases of the respiratory apparatus. In bestowing some consideration on these points I shall not detain the reader with minute descriptions, still less engage in discussions relative to the mechanism of respiration, which, however much of interest they may possess for one desirous of investigating the subject fully, are not of special importance in view of pathological relations.