From Chapter 3:
Another tract which may be classed with Venner's "Treatise" was the "Nepenthes or the Vertues of tobacco," by Dr. William Barclay, which was published at Edinburgh in 1614. This is sometimes referred to and quoted, as by Fairholt, as if it were a whole-hearted defence of tobacco-taking. But Barclay enlarges mainly on the medicinal virtues of the herb. "If Tabacco," he says, "were used physically and with discretion there were no medicament in the worlde comparable to it"; and again: "In Tabacco there is nothing which is not medicine, the root, the stalke, the leaves, the seeds, the smoake, the ashes." The doctor gives sundry directions for administering tobacco—"to be used in infusion, in decoction, in substance, in smoke, in salt." But Barclay clearly does not sympathize with its indiscriminate use for pleasure. "As concerning the smoke," he says, "it may be taken more frequently, and for the said effects, but always fasting, and with emptie stomack, not as the English abusers do, which make a smoke-boxe of their skull, more fit to be carried under his arme that selleth at Paris dunoir a noircir to blacke mens shooes then to carie the braine of him that can not walke, can not ryde except the Tabacco Pype be in his mouth." He goes on to say that he was once in company with an English merchant in Normandy—"betweene Rowen and New-haven"—who was a merry fellow, but was constantly wanting a coal to kindle his tobacco. "The Frenchman wondered and I laughed at his intemperancie."

From Chapter 8:
The allusion in these verses to a "satiric wipe" refers to a passage in the poem entitled "Conversation," which Cowper had written in the previous year, 1781. In this passage tobacco is abused in terms which Cowper clearly felt to need modification after his personal intercourse with such a smoker as his friend Bull. In describing, in "Conversation," the manner in which a story is sometimes told, the poet says:

The pipe, with solemn interposing puff,
Makes half a sentence at a time enough;
The dozing sages drop the drowsy strain,
Then pause and puff—and speak, and pause again.
Such often, like the tube they so admire,
Important triflers! have more smoke than fire.