are augmented in size and acquire firmness by exercise, and become atrophied by being kept in a state of immobility, as in paralysis, where nervous stimulation is intercepted, or in fractures or painful chronic affections, where their motion is impracticable or would aggravate pain. In the next place, it must be observed that this exaggeration of the vital properties of a part, if it exceed certain limits, produces disease, and that the transition from congestion to inflammation is neither abrupt nor difficult. It is on this account that the highest degree of health, when all the functions are performed with an activity that diffuses a joyous sense of well-being over the economy, sometimes portends disease. If the locomotive muscles, for example, are too severely tasked, the congestion becomes fixed, and hence the soreness and stiffness which are complained of after inordinate or prolonged exertion, and we are told that it is not unusual for the muscles of the thighs of soldiers, after forced marches, to become painful and produce a chill and fever-to inflame and suppurate as after the most violent attacks of rheumatism.* Having premised these general observations we proceed to seek for sources of infantile disease, first, in the establishment of the respiratory function.

The first and most urgent want which the infant experiences is atmospheric air, without which its existence cannot be prolonged beyond a few minutes: and consequently pulmonary respiration is the first of the functions, progressively established, which is called into exercise. The development of the lungs is complete at birth, and so likewise is the pulmonary artery, destined to convey to them venous blood for its conversion into arterial; but the revivification of the blood having hitherto been effected by another provision, the lungs

*Broussais' Physiology.

existed in a collapsed state and the main current of the blood was turned from them by temporary channels. The fetal provision being abolished, it is indispensable that pulmonary respiration be promptly established; but this may be impeded by many causes, and hence asphyxia neonatorum comes in for a large share of the mortality of infants. In New York, the number of deaths from this cause, or still-born, in sixteen years, was 4,793, being in the ratio of one to twenty of the whole number, and one to four and a half of such as died within the first year.

In pursuing the diseases which threaten the existence of infants through this function, it must be observed that even if respiration be established, the lungs are peculiarly liable to congestion, producing either simple engorgement or extravasation into their tissue. Recent researches, particularly at the Foundling Hospital of Paris, have proved the frequency of this morbid state, and that pulmonary apoplexy, as extravasation is termed, is a much more common occurrence in children than adults. Nor is it diffiuclt to account for the increased liability of new born infants to pulmonary congestion; it is, as we may fairly presume, only an excess of the normal congestion existing in all organs during the active performance of their functions, induced the more easily, if it may be so expressed, in consequence of the raw and undisciplined state of the lungs at this period;—the stimulation and expansion of the lungs invite the afflux of blood into their tissue, the vessels of which are less able to bear the sudden inundation because their contractility has not acquired strength by exercise.

Inflammation of the lungs is not an unusual sequence of these congestions, and at this period it differs from the same disease in adults in being strictly confined to the lungs, with

THE

WESTERN JOURNAL

OF

MEDICINE AND SURGERY.

JANUARY, 1840.

ART. 1.— An inquiry into some of the causes of the Mortality of Infants. By HENRY MILLER, M. D.

AMONG the many disclosures of medical statistics, which serve to enlighten us in relation to all that can affect health and longevity, none stands out more prominently than the precariousness of life in the earlier periods of our existence. Life, at best but brief and in all its stages environed by causes inimical to its continuance, is then peculiarly threatened with extinction. From a comparison of the most accurate obituary registers, it may be deduced that the deaths of children under a year old, constitute about a fifth of the whole number oocurring for a series of years. In Paris, for example, during the year 1818, the number of deaths was

22,421, whereof 3,942 or 17 per cent. were under the age of one year: the deaths in Philadelphia during a period of twenty years, include rather a larger proportion of infants than the average assumed; in New York, according to the tables compiled by Dr. Lee,* embracing a period of sixteen years, twenty-five per cent., or one fourth the whole number of deaths were children under one year- the total number of deaths being 83,783, of which 21,330 were infants. The ratio of children decreases after the first year, being but 7,866 in New York, from one to two years; 6,787 only from two to five years; and it is remarkable how much greater risk to life the first than the second five years involve; thus, of the 83,783 comprised in these tables, 35,983 were children under five years, while only 2,232 were between five and ten years old.

But it is foreign to my design to enter into statistical details any farther than to establish the fact, that a proportionally larger number of children die within the first year than adults, and an inquiry into some of the causes of this greater mortality, it is hoped, will be not without interest and practical utility.

It is too obvious to need particular remark, that one cause of the greater mortality of children is their exposedness to certain diseases which, whether issuing from Pandora's box or not, are dispersed over the world, and may be said, almost without a figure, to guard the avenues to life. These diseases. not excepting croup and hooping-cough, often prevail epidemically, and carry off multitudes of children. Between some of them and the infantile constitution there is a particular affinity, adults being but seldom affected by them.

*American Journal of Medical Sciences, No. xxxvii.

Others, especially the Exanthemata, small-pox, measels, scarlet fever, &c., are not so exclusive in the selection of their subjects; but never wholly extinct, and often raging as epidemics, children are more apt to be assailed by them, because the constitution is not generally susceptible of a second attack, and but few have been ushered into manhood without having run their gantlet. But there are sources of disease to children, that are connate and do not adhere to them when grown up, which it most concerns us to investigate, and the first of these deserving attention, is a physiological peculiarity that is strongly stamped on their constitution, viz.: Their excitability or vitality, in all the tissues and organs which it pervades, is more vivacious but less energetic than that of adults. In confirmation of this we may refer to the manner in which some of their most important vital actions are performed. The contractions of the heart are much more rapid, the pulse of the infant being nearly double in frequency that of the adult, varying from 120 to 140 beats in a minute: at the same time it is evident that the pulsations are not so strong and the blood is not sent out in as bold a current in the vessels through which it circulates. Indeed, it is plain that the increased frequency is a compensation for deficient force, as the pulse of adults, who are suffering from debility, becomes frequent when it loses strength and volume. Respiration is carried on with greater rapidity, the inspirations numbering from 35 to 40 in the minute or nearly double. those of the healthy adult; and yet, notwithstanding this activity of the respiratory process, the infant consumes less oxygen, showing that the function is less efficiently performed. The calorific function, as it may with propriety be called, although no special organ be allotted to it, is less energetic,as has been proved by Dr. Edwards, who found that the