A perfect knowledge of all these particulars would constitute as complete a history of any disease, as in the present state of knowledge we can expect to form. But it is also not unreasonable to inquire

3. What is the nature and essence of the cause, what circumstances produce it, what are the primary laws which it obeys, and what is the mode in which it produces those symptoms which we have before empirically determined? Rightly considered, these questions do not belong to an impracticable transcendentalism, but only to the most difficult and inaccessible portions of our science. They may not, indeed, be determined in this age; but there is reason to hope that, guided by an advanced physical science, our descendants may explore the gloomy recesses of this labyrinth, and illumine what to us is now almost impenetrably obscure.

We have made these introductory remarks for the purpose of indicating the method and spirit in which we shall examine the works before us. They are both valuable additions to the extensive literature of this subject, and are marked by many of those qualities of accurate observation and research, which speak so favorably for the advance of medical science in

these countries.

At the present time we shall confine our remarks almost entirely to the influenza of 1847, and shall refer to other epidemics merely for elucidation and comparison. We do this especially, because it is understood that the Sydenham Society are now engaged in compiling a history of catarrhal epidemics, and many points will therefore be profitably deferred until this great work appears ;* we shall proceed at once, therefore, to our subject.

1. The determination of the typical form of influenza. That form by which the presence of the active cause can be certainly recognised, is evidently the fundamental and necessary condition of all other inquiries. If we are not certain about the diagnosis of the disease, we are continually liable to serious errors, when we seek to determine from statistics the laws of diffusion of the specific agent. It is absolutely essential that a definite term shall correspond to a definite disease in the mind of each observer; otherwise statistics collected from numerous sources become but a mass of figures, whose apparent accuracy is as fatal, or even more fatal to science than conclusions drawn from a narrow and circumscribed field of inquiry. And although in the case of influenza it might be supposed that there can be no mistake about the grand facts, that there can be no doubt that such a disease is or has been prevailing, and that it has prostrated half a community with symptoms too remarkable to be mistaken; still it does appear that a great looseness exists in the use of this term. This has been especially apparent in former epidemics; thus in 1833, when the weekly mortality of London was trebled for two or three weeks, and doubled for three or four more, from influenza, the total number of deaths directly ascribed to this disease, during the whole time, was only 89.† In other epidemics every bronchitic attack has been called influenza, and every death in which influenza has played a subordinate share has been entirely ascribed to it. *This promises to be one of the most important works sent forth by the Sydenham Society. We regret, however, to be informed that it is intended to carry down the history only to the end of 1837. We must question the propriety of leaving out the recent epidemics, respecting which so much material has been brought together. We should hope, if not too late, that this determination might be reconsidered.

Registrar-General's Report, p. 9.

Both these errors may have vitiated the records of the last epidemic. Thus it appears, that although in nine weeks the excess of deaths in London, over the average number for the same time, reached the astonishing number of 6966, only 1157 were actually returned as attributable to the epidemic disease. On the other hand, we shall have occasion to point out that several distinct diseases have been included under this appellation. These facts show the importance of an accurate diagnosis, if we are desirous of availing ourselves of the admirable machinery for registering the cause of death, which is now in use. But a correct diagnosis can only be formed by analysing the results of careful observations, displaying the disease in its simple and normal form, and then by synthesis, adding to this outline the several pathological states which more or less intimately ally themselves with it. And in a correct statistical return, these allied pathological states, as well as the accidental complications, ought to be stated.

Not, however, to dwell too long on these preliminary questions, we will proceed at once to lay Dr. Peacock's views before our readers.

After an introductory review in which the outset of the epidemic is sketched out, and to which we shall presently return, Dr. Peacock proceeds to detail the symptoms of the disease Adopting to its fullest extent the view that influenza depends on a specific agent, he first isolates the elementary form of the disease, which he terms " simple catarrhal fever." He then in the following chapters discusses this catarrhal fever "with pulmonary complication," and "with predominant disorder of the abdominal organs." The " simple catarrhal fever" of 1847 generally attacked suddenly with chilliness and shivering, which was rapidly succeeded by an immediate and evident impression on the mucous membrane of the nose, mouth, frontal sinuses, trachea, and bronchial tubes to a greater or less extent; accompanying this, there were severe darting neuralgic headaches, aching of the limbs, listlessness, great mental depression, complete anorexia, and an extraordinary weakness, which, according to our observations, bore a close ratio to the extent of pulmonary affection, and consequently to the severity of the disease. The average duration of illness was from 3 to 5 days in the mildest cases, and from 7 to 10 in the more severe form. Towards the termination of the complaint, rheumatic affections, especially of the face and head, assuming an intermittent type, often occurred. Occasionally there was diarrhea, and the complaint subsided with free perspiration. The auscultatory signs were those merely of bronchitis, dry rhonchi in some parts, and harsh vesicular murmur in others. This form required only gentle diaphoretic medicine; or, if there was much dyspnoa and tightness across the chest, an emetic followed by Dover's powder and nitrate of potash was found to be servicable. Colchicum and quinine were given in the rheumatic sequelæ.

The pulmonary complications are divided into four forms:

1. Capillary bronchitis. 2. Bronchitis supervening on tuberculous disease of the lungs. 3. Bronchitis with disease of the heart or aorta. 4. Pneumonia.

Acute or sub-acute capillary bronchitis was the most frequent complication. Out of twenty-eight cases of influenza, with severe pulmonary affection, in the Royal Free Hospital, eleven presented this variety. Out

of these eleven, four patients only were, previous to the attack of influenza, in perfect health. The symptoms were at first those of ordinary influenza; then the chest symptoms increased in severity, the cough became paroxysmal; there was dyspnoea quite disproportionate at the first to the cough, or to the physical signs; the expectoration was scanty, and consisted of small yellowish pellets, forming tenacious masses of a peculiarly modulated form. The pulse was rapid (120-40), the tongue covered with a whitish-brown fur, and the prostration was extreme. The only auscultatory signs were roughness of the inspiratory murmur, with occasional sibilus, and slight crepitation at the back. There was soreness and constriction at the chest, but no acute pain.

The crepitation soon extended over a greater or less extent of both lungs, but was unattended by dullness on percussion. Speedily the dyspnea became so intense as sometimes to prevent the patient from lying down; the lividity of the lips and face increased, and the eyes became prominent; the cough was now very frequent, and the sputa were viscid, of a greenish yellow colour, without air-bells, and often streaked with blood. The respirations were quickened-in one case they reached 72 per minutethe pulse was either exceedingly quick (140-60) or intermittent, and consequently rather slower.

On referring to the illustrative cases, it appears that the case in which the respirations reached 72 per minute, was that of a man aged 26, labouring under old hemiplegia, and who was suddenly attacked with capillary bronchitis after an anomalous epileptic seizure; the pulse was 136 per minute, therefore the respirations were to the pulse as 1 to 1.8. On the following day the respirations were 40, the pulse 72 per minute, the ratio being thus exactly preserved, 1 to 18; in this case the cerebral symptoms possibly modified the ratio. In calculating, however, the relation between the number of respirations per minute, and the pulse, in all the cases of capillary bronchitis in which the point is noted, we do not find any uniform connexion between the extent of the disease, and the disturbed ratio of the pulse and respiration-movements. Thus the first recorded case was one of slight capillary bronchitis; on the fifth day, when the observation was made, the ratio of respiration to the pulse was as 1 to 29. In the second case, also one of slight bronchitis, the ratio on the fourteenth day was as I to 3.8. In the third case, which was very severe, the ratio on the eighth day was also 1 to 3.8. In the 5th case, four days before death, the ratio was 1 to 3. In the sixth case, four days before death, the ratio was 1 to 34. So that the general rule was, that the respirations were relatively more quickened than the pulse in all the cases, but not appreciably more, as far as these very few cases indicate, in the severe than in the slight cases.

After the disease had lasted some little time, the physical signs were modified by rapidly developed emphysema of some portions of the lung, while others became dull from more or less extensive hepatization. This emphysema, as far as could be made out by physical examination during life, or post-mortem examination after death, often occurred in a slight degree throughout the whole extent of the lungs. It is not difficult to conceive, that the laboured inspiratory movements would tend to force the air past the viscid mucus, in a greater degree than the feebler expiratory movements could again expel it. Consequently, the residual air accumu

lating in the cells and smallest bronchial tubes, and pressing upon membranes which perhaps had suffered alteration from the inflammatory action, produced a slight but universal dilatation, which no doubt increased the dyspnoea, already sufficiently urgent on account of the universal and equal affections of both lungs. It has been long known that influenza often left emphysema as a sequel, and, in fact, this must evidently be a common result; Dr. Peacock, however, has noticed that the emphysema was often transient; during convalescence the abnormal resonance gradually disappeared, and was even in some cases succeeded by slight general dull

ness.

This capillary bronchitis was distinguished from pneumonia by the greater severity of the general symptoms; by the tendency of the fine crepitation of the early stage to pass into subcrepitant and mucous ráles rather than to give place to evidences of condensation; and by the peculiar characters of the cough, which was paroxysmal and not attended by pain, and of the expectoration,* which consisted of whitish viscid pellets cohering into irregular masses, and was destitute of the glairy adhesive character, russet colour, and small air-bubbles of pneumonic expectoration. These characters, however, Dr. Peacock mentions, will distinguish only the most marked forms; and there is no doubt that almost every case of capillary bronchitis depending on influenza, is combined with more or less lobular or even lobar pneumonia on the one hand, and with general inflammation of the larger bronchial tubes and trachea on the other.t

Out of eleven cases of influenza, complicated with capillary bronchitis, no less than five died. Two of the patients, however, had been ill for some time previous to the attack, and after death "presented such advanced organic disease of the lungs as would have terminated existence had not life been more rapidly destroyed by the bronchial inflammation." Two of these other three cases could not be examined after death, so that there is only a single post-mortem examination of the sole complication. And even here there was old standing emphysema of both lungs, at least if the case referred to be that of Ann Gilbert (case 6, p. 131); so that we cannot discover any account of the post-mortem appearances in an uncomplicated case of capillary bronchitis and lobular pneumonia. But judging from the appearances presented by the lungs in other cases complicated with capillary bronchitis, in addition to still more important lesions, Dr. Peacock gives the following account:

"The peculiar feature presented by examination after death from this form of disease was the extremely inflated and emphysematous condition of the lungs, which in lieu of collapsing when the chest was laid open, in some cases even protruded from the cavity. This condition was not limited to certain portions of the lungs in which there were larger or smaller dilated cells, as in ordinary cases of emphysema, but was evidently due to a general, and tolerably equal inflation of the entire pulmonary tissue. . . . The mucous membrane of the bronchial tubes was reddened, and the injection increased from the larger toward the smaller tubes. . . . Pneumonic condensation, either of the lobar or lobular form existed to a greater or less

The chemical and microscopical examination of the sputa in the bronchitis and pneumonia of influenza is well worthy of study. (Magendie.)

†M. Beau has lately (Archives Genérales de Médecine, Septembre, 1848) called attention to catarrhal inflammation of the trachea, as distinguished entirely from plastic tracheitis or croup, and from the common forms of bronchitis. In influenza, the whole laryngo-bronchial tube is more or less profoundly affected.

extent in every instance. In the lobular form, the solidified masses varied from patches involving two, three, or more lobules, to others of much greater extent, and were in all cases distinctly bounded by the interlobular septa." (pp. 31-2).

In the three cases in which there was no phthisis, death occurred on the ninth, tenth, and twelfth days. In the case of recovery, the ordinary duration of the cases was from fourteen to twenty-one days. When pneumonia was the complication, there was always more or less coexistent bronchitis; there was also present an unusual degree of depression of strength; the cough was severe; the expectoration consisted of brownish coloured and viscid masses, with small air bells, intermixed with glairy transparent or opaque fluid, containing large bubbles of air; the physical signs were those of pneumonia. Both the pulse and the respiratory movements were slower than in the cases with capillary bronchitis. In one case the respiration was to the pulse on the seventh day of the disease as 1 to 22; in another, on the fourth day, as 1 to 3; in a third, of uncertain duration, as 1 to 4. The average of the respirations was from 28 to 44 per minute; and of the pulse, from 80 to 100. The variations of the ratio were from 1 to 18, to 1 to 35. This complication, which occurred in six out of forty-eight severe cases, did not prove fatal in a single case, and yielded, indeed, to tolerably mild treatment.

A laryngeal complication existed in many cases, although no case which could be termed actual laryngitis came under Dr. Peacock's notice.

Neither pleurisy nor pericarditis appear to have been common complications; we find an incidental mention of one case of circumscribed pleurisy, and in a second case, marks of recent pleurisy were found after death. In two fatal cases, effusion into the pericardium was suspected in one, and in the other recent pericarditis was found.

Dr. Peacock then proceeds to a general "review of the results of catarrhal fever with pulmonary complication:" 48 cases were admitted into the Free Hospital, 24 of each sex, and of these 3 men and 6 women died. We must confess, however, that we cannot make out how these numbers are determined. We have been informed that 5 cases of capillary bronchitis died, but we find no statement of any other deaths from pulmonary complaints, except 1, which case, however, Dr. Peacock, at page 64, expressly excludes. At page 56 we have, it is true, a reference to 4 fatal cases, complicated with disease of the heart and bronchitis, and we presume that Dr. Peacock has included these in the table at page 46. Admitting that this surmise is correct, it appears that 2 persons died from the supervention of influenza on phthisis; I from the supervention of influenza on old emphysema; 2 from pure influenza, that is, considering the capillary bronchitis as an intrinsic part of it; 2 from influenza complicated with peri and endo-carditis; 1 from influenza supervening on old heart-disease; and 1 from aneurism of the aorta after the influenza had disappeared. Excluding this last case, we have 8 cases of influenza which proved fatal out of 48, and of these 4 were labouring under previous severe organic disease. The other 4 then present the actual mortality of the influenza per se, irrespective of the influence exerted by it on organic diseases, whose course it accelerated, or which caused it to prove fatal. But it must be remembered that this number (4 cases out of 48) does not express the number of deaths to the whole number of cases of influenza; as only the severest cases were admitted into the wards, and. 7-IV.

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