_Infant diseases_ every where furnish a vast supply to the gloomy realms of Pluto; and this calamity is infinitely aggravated by the noxious atmosphere of cities and towns. At birth, an infant is not only ushered into a new world, but every function of its frail body undergoes new and sudden changes. From the human oven of 96 degrees of heat, it is launched into a variable climate of heat and cold. A new element of many thousand pounds weight then presses upon the surface of its body. This atmospherick fluid, adulterated in cities with innumerable impurities and feculencies is drawn into its lungs: its diaphragm and muscles of respiration then begin to act, the lungs expand, and the respiration commences. The passage between the auricles of its heart and arterial duct are gradually closed up; the sphere of the circulation is extended; the whole current of blood in its frequent revolution hourly, passes through the lungs; the circulation through the navel-string, and through which it had till then drawn its principal nourishment, instantly ceases: food, for the first time, begins to be taken in by its mouth; the digestive, with all the numerous secretory and excretory organs, then begin to perform their different offices; the tender creature is exposed to sounds, in a few days to light; the bones at the superior part of its head gape, and the brain is there defended by skin only; its head, belly, liver, and lymphatic glands, are large, and its extremities slender; the fetal brain is destitute of ideas; its bones are little more than gristles and cartilages; its muscles are soft, flabby, and without swell or expression; the greatest part of its time is spent in a state of inactive vegetation; it is unable for several months to support its own weight, or to take nourishment, and is then the most feeble and helpless of all the animal creation. With such delicate machinery, it has soon to encounter pain and disease; the assaults of internal and external enemies; when its crazy beams and bolts are easily shook asunder in the first storm.
The acute diseases of early infancy; that is, under two years of age (small pox, measles, and a few others excepted) are in the London registers, principally accumulated into two aggregate heaps, _Convulsions and Teething_: the former of which forms a dreary catalogue of astonishing magnitude in London funerals; amounting to nearly one third of the whole mortality in the metropolis. But convulsions and teething are terms too indefinite. Every infant disease, not immediately obvious to the senses, is thrust into these two articles by the ignorant reporters. If we consider the term scientifically, convulsions, in multitudes of cases, convey no more intelligence of the nature of the disease, than if they had said the child died from want of breath. Let us therefore examine, whether the collected observations of medical authors will not illuminate many dark and defective parts of the publick registers, respecting infant mortality. Infants are exempt from a multitude of the acute and chronic diseases of adults: they rarely suffer so early in life from hereditary diseases, cares, passions of mind, painful impulses of retentive memory, severe study, intemperance, hard labour, the inclemency and vicissitudes of the seasons, and so on. The principal diseases of infancy may be comprehended under the following: convulsions, inward spasms and tetanus, colick, vomiting, acidity, indigestion, flatulence, diarrhœa and gripes, thrush, dentition, hectic fever and atrophy, rickets, scald head, rash, dropsy of the head and spine, inguinal ruptures; together with small pox, measles, hooping cough, worms, and a few others already described.