Page:Popular Science Monthly Volume 40.djvu/849

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URING the century which preceded the American Revolution the science of the colonies, like their commerce, was tributary to that of the Old World. Fabulous reports in regard to the natural resources of America had been brought home by European voyagers, and the cultivators of all sciences and arts were looking to that vast unexplored region for products which should increase the knowledge of the naturalist, the resources of the physician and the agriculturist, the profits of the merchant, and the enjoyment of the man of leisure. The function of those colonists who inclined to natural history was that of explorers and collectors, and among the earliest and most notable of these American collectors were the subjects of this sketch.

The grandfather of the elder Bartram, also named John, came from Derbyshire, England, to Pennsylvania in 1682. He brought his wife, three sons, and one daughter, and settled near Darby, in Delaware (then Chester) County. The third son, William, was the only one who married, his wife being Elizabeth, daughter of James Hunt, Both families belonged to the Society of Friends. The children of William were John (the botanist), James, William, and a daughter who died young. The second William went to North Carolina and settled near Cape Fear; John and James remained in Pennsylvania.

The date of birth was March 23, 1699. But little is on record concerning his early years. Like the majority

, blood charged with poison which have escaped from the skin and lungs, and been rebreathed into the system—would have the same favoring effect upon them as the un-healthy tissue. Both are likely to present them with the food they require. If this be so, then just as the bacteria that cause disease are favored by the external poisons they find ill vitiated air, so also they may be internally favored by the unhealthy slate of the bronchial and lung tissues of those persons who habitually breathe the poisons of shut-up rooms. Thus, these organic poisons, both within and without a man, would tend to make him a prey to those illnesses in which the success of the germ depended upon its proper—might we say—food being supplied to it; and it would seem probable that, by constant attention to the purity of the air which we breathe, we might do much toward securing individual exemption from the danger of infectious diseases. An instructive passage in Dr. Carpenter (p. 365) which bears on this point should be read. It is also worth quoting Prof. Nussbaum (see an interesting article by Mrs. Priestley, May, Nineteenth Century, p. 825): "It is known with certainty that the cholera bacillus is dangerous only to those persons whose stomach is not in a healthy state, and jeopardizes life only when it passes into the intestines. A healthy stomach will digest the bacillus, and therefore it does not reach the intestines in a living state." It is, perhaps, right to refer here to a theory that in the blood and connective and lymphatic tissues (Klein, p. 243) there exists a clan of protective cells (phagocytes), whose office it is to overpower invading bacteria of a dangerous character; and, according to Metschnikoff (Ann. de l'Institut Pasteur) these can, in case of need, emigrate to any part of the body which is invaded by parasites.