man.

But Franklin considered himself a very temperate When writing his Autobiography, in his old age, he reminds his descendants that to temperance their ancestor "ascribes his long-continued health and what is still left to him of a good constitution."

Like most of those who live to a great age, he was the child of long-lived parents. "My mother," he says, "had likewise an excellent constitution; she suckled all her ten children. I never knew either my father or mother to have any sickness but that of which they died, he at eighty-nine and she at eighty-five years of age."

He was fond of air-baths, which he seems to have thought hardened his skin and helped it to perform its functions, and when in London in 1768 he wrote one of his pretty letters about them to Dr. Dubourg in Paris.

"You know the cold bath has long been in vogue here as a tonic; but the shock of the cold water has always appeared to me, generally speaking, as too violent, and I have found it much more agreeable to my constitution to bathe in another element, I mean cold air. With this view I rise almost every morning and sit in my chamber, without any clothes whatever, half an hour or an hour, according to the season, either reading or writing. This practice is not in the least painful, but, on the contrary, agreeable; and if I return to bed afterwards, before I dress myself, as sometimes happens, I make a supplement to my night's rest of one or two hours of the most pleasing sleep that can be imagined. I find no ill consequences whatever resulting from it, and that at least it does not injure my health, if it does not in fact contribute much to its preservation. I shall therefore call it for the future a bracing or tonic bath." (Bigelow's Works of Franklin, vol. iv. p. 193.)

Some years afterwards, while in Paris and suffering severely from gout in his foot, he used to expose the

foot naked out of bed, which he found relieved the pain, because, as he supposed, the skin was given more freedom to act in a natural way. His remarks on air-baths were published in the early editions of his works and induced many people to try them. Davis, in his "Travels in America," says that they must have been suggested to him by a passage in Aubrey's "Miscellanies;" but, after searching all through that old volume, I cannot find it. Franklin, however, made no claim to a discovery. Such baths have been used by physicians to strengthen delicate persons, but in a more guarded and careful manner than that in which Franklin applied them.

It was characteristic of his genial temperament that he loved to dream in his sleep and to recollect his dreams. "I am often," he says, "as agreeably entertained by them as by the scenery of an opera." He wrote a pleasant little essay, addressed to an unknown young lady, on "The Art of Procuring Pleasant Dreams," which may be said to belong among his medical writings. Fresh air and ventilation are the important dream-persuaders, and bad dreams and restlessness in bed are caused by excess of perspirable matter which is not allowed to get away from the skin. Eat less, have thinner and more porous bedclothes, and if you are restless, get up, beat and turn your pillows, shake all the sheets twenty times, and walk about naked for a while. Then, when you return, the lovely dreams will

come.

Closely connected with his faith in air-baths was his opinion that people seldom caught cold from

exposure to air or even to dampness. He wrote letters on the subject and prepared notes of his observations. These notes are particularly interesting and full of curious suggestions. The diseases usually classed as colds, he said, are not known by that name in any other language, and the name is misleading, for very few of them arise from cold or dampness. Indians and sailors, who are continually wet, do not catch cold; nor is cold taken by swimming. And he went on enumerating the instances of people who lived in the woods, in barns, or with open windows, and, instead of catching cold, found their health improved. Cold, he thought, was caused in most cases by impure air, want of exercise, or over-eating.

"I have long been satisfied from observation, that besides the general colds now termed influenzas (which may possibly spread by contagion, as well as by a particular quality of the air), people often catch cold from one another when shut up together in close rooms and coaches, and when sitting near and conversing so as to breathe in each other's transpiration; the disorder being in a certain state. I think, too, that it is the frouzy, corrupt air from animal substances, and the perspired matter from our bodies, which being long confined in beds not lately used, and clothes not lately worn, and books long shut up in close rooms, obtains that kind of putridity which occasions the colds observed upon sleeping in, wearing, and turning over such bedclothes or books, and not their coldness or dampness. From these causes, but more from too full living, with too little exercise, proceed, in my opinion, most of the disorders which, for about one hundred and fifty years past, the English have called colds.”

Much of this is true in a general way, for medical practitioners have long held that all colds do not arise from exposure or draughts; but they do not admit that colds can be taken from turning over

old books and clothes, although the dust from these might make one sneeze.

John Adams and Franklin while travelling together through New Jersey to meet Lord Howe, in 1776, discussed the question of colds, and the former has left an amusing account of it. The taverns were so full at Brunswick that they had to sleep in the same bed. Franklin insisted on leaving the window wide open, and discoursed on the causes of colds until they both fell asleep.

"I have often asked him whether a person heated with exercise going suddenly into cold air, or standing still in a current of it, might not have his pores suddenly contracted, his perspiration stopped, and that matter thrown into the circulation, or cast upon the lungs, which he acknowledged was the cause of colds. To this he never could give me a satisfactory answer, and I have heard that in the opinion of his own able physician, Dr. Jones, he fell a sacrifice at last, not to the stone, but to his own theory, having caught the violent cold which finally choked him, by sitting for some hours at a window, with the cool air blowing upon him." (Adams's Works, vol. iii. p. 75.)

In some of his letters Franklin denied positively that colds could be taken by exposure. He got a young physician to experiment on the effect of nakedness in increasing perspiration, and when he found, or thought he had found, that the perspiration was greater than when the body was clothed, he jumped to the conclusion that exposure could not check perspiration. In a passage in his notes, however, he seems to admit that a sudden cold or a draught might check it.

He wrote so well and so prettily on colds that people began to think he was the discoverer of their causes,