From Chapter 2:
The properly accomplished gallant not only professed to be curiously learned in pipes and tobacco, but his knowledge of prices and their fluctuations, of the apothecaries' and other shops where the herb was sold, and of the latest and most fashionable ways of inhaling and exhaling the smoke, was, like Mr. Weller's knowledge of London, "extensive and peculiar." It was knowledge of this kind that gained for a gallant reputation and respect by no means to be acquired by mere scholarship and learning.

From Chapter 5:
At the time of the Great Plague all kinds of nostrums were sold and recommended as preservatives or as cures. Most of these perished with the occasion that called them forth; but the names of some have been preserved in a rare quarto tract which was published in the Plague year, 1665, entitled "A Brief Treatise of the Nature, Causes, Signes, Preservation from and Cure of the Pestilence," "collected by W. Kemp, Mr. of Arts." In the list of devices for purifying infected air it is stated that "The American Silver-weed, or Tobacco, is very excellent for this purpose, and an excellent defence against bad air, being smoked in a pipe, either by itself, or with Nutmegs shred, and Rew Seeds mixed with it, especially if it be nosed"—which, I suppose, means if the smoke be exhaled through the nose—"for it cleanseth the air, and choaketh, suppresseth and disperseth any venomous vapour." Mr. Kemp warms to his subject and proceeds with a whole-hearted panegyric that must be quoted in full: "It hath singular and contrary effects, it is good to warm one being cold, and will cool one being hot. All ages, all Sexes, all Constitutions, Young and Old, Men and Women, the Sanguine, the Cholerick, the Melancholy, the phlegmatick, take it without any manifest inconvenience, it quencheth thirst, and yet will make one more able, and fit to drink; it abates hunger, and yet will get one a good stomach; it is agreeable with mirth or sadness, with feasting and with fasting; it will make one rest that wants sleep, and will keep one waking that is drowsie; it hath an offensive smell to some, and is more desirable than any perfume to others; that it is a most excellent preservative, both experience and reason do teach; it corrects the air by Fumigation, and it avoids corrupt humours by Salivation; for when one takes it either by Chewing it in the leaf, or Smoaking it in the pipe, the humors are drawn and brought from all parts of the body, to the stomach, and from thence rising up to the mouth of the Tobacconist, as to the helme of a Sublimatory, are voided and spitten out."