Democritus Junior to the Reader, page 16

[p. 16]
My intent is no otherwise to use his name than Mercurius Gallobelgicus, Mercurius Britannicus, use the name of Mercury, Democritus Christians,* etc.;...

* R.B.: Auth. Pet. Besseo, edit. Coloniæ, 1616.

Mercurius was a brand of newspapers, or more properly, news books. The idea was copied after the Mercure française, launched in France in 1611. First to appear was the Mercurius  Britannicus, which in 1625 became the first English news periodical to carry that title.
(from Jonathon Green, The Vulgar Tongue: Green's History of Slang, Oxford University Press, 2011, p. 100)

The dates would seem to suggest that this name was thrown in in a later edition (Burton was a notorious re-writer).

[Edit, Feb. 27:] I have just discovered a long-running series of contributions to the Oxford journal Notes & Queries submitted in the first decade of the twentieth century by Edward Bensly, a scholar whose home institution was "The University" of Adelaide, South Australia. He takes A.R. Shilleto to task, rectifying errors in his late-nineteenth-century edition of Anatomy... and filling in the gaps. On the topic of Mercurius, this erudite contributor notes in the Dec. 3, 1904 issue (N&Q, 10th ser., vol. II, p. 442): "'Mercurius Britannicus.' The author of Mundus alter et idem (Bishop Joseph Hall)." Although my first guess missed the mark, I'm leaving it in: I imagine Burton's smirk as the news-paper started coming out, lending new meanings to his allusion.

Hall's work sounds deserving of a reading blog of its own: to start, I thought I'd consult Encyclopædia Britannica, which tells us that the author was "[e]ducated under Puritan influences at the Ashby School and the University of Cambridge (from 1589), [where] he was elected to the university lectureship in rhetoric. He became rector of Hawstead, Suffolk, in 1601 and concentrated chiefly on writing books for the money 'to buy books.'” (I thoroughly sympathize!) Reading on: "Mundus Alter et Idem (c.1605; The World Different and the Same), an original and entertaining Latin satire that influenced Jonathan Swift’s Gulliver’s Travels (1726), dates from this period..." Well, encyclopedic namesake, that's not much. Wikipedia offers a well-annotated synopsis which I find delightful: 

Joseph Hall, Mundus alter et idem (1605), title page.

The narrator takes a voyage in the ship Fantasia, in the southern seas, visiting the lands of Crapulia, Viraginia, Moronia and Lavernia (populated by gluttons, nags, fools and thieves, respectively). Moronia parodies Roman Catholic customs; in its province Variana is found an antique coin parodying Justus Lipsius, a target for Hall's satire which takes the ad hominem beyond the Menippean model.

Mercurius Gallobelgicus was a Latin periodical, which, according to Wikipedia, first appeared in 1592 in Cologne. [Edit, Feb. 27:] Bensly adds: "It was written by Michael von Isselt ('M. Jansonius') and others. An English translation of part of this work was printed at London in 1614."

The mention of Mercury is more than a passing analogy. Mercury was associated with medicine, as well as wit.

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Democritus Christianus refers to the title of a contemporaneous work by Pierre de Besse (1567–1639), Le Démocrite chrestien... (1615), which Burton cites in the Latin translation published a year later. In 1612, de Besse had published Le Héraclite chrestien, which Burton must have read, as well. Heraclitus and Democritus were often paired together: the dichotomy dates back to Antiquity and the Italian Antonio Filermo Fregoso (died c.1505) is credited with its revival in his oft-reprinted double poem entitled "The Laughter of Democritus" and "The Weeping of Heraclitus" (1507). 

In his essay "On Democritus and Heraclitus," Montaigne sums up the duality: 

“Democritus and Heraclitus were both philosophers; the former, finding our human circumstances so vain and ridiculous, never went out without a laughing and mocking look on his face: Heraclitus, feeling pity and compassion for these same circumstances of ours, wore an expression which was always sad, his eyes full of tears.”

Michel de Montaigne, The Complete Essays, trans. M.A. Screech (Penguin Classics, 2003), Book I, essay 50. 

De Besse wanted to "Christianize" the two ancient philosophers, and used the tears of the one to commiserate with human misfortune and the laughter of the other to mock worldly vanity.

Crispijn van de Passe (I) (1574–1637), The Upside-Down World (from Rijksmuseum).

[p. 16]
Democritus, as he is described by Hippocrates* and Laertius**...

* R.B.: Hip. Epist. Damaget. ** Laert. lib. 9. [Shilleto: cap. 7]

Here Burton refers to Diogenes Laertius's Lives of Eminent Philosophers, which devotes a section of Book 9 to Democritus, and a series of pseud0-Hippocratic letters. These letters seem to be easily available only in Émile Littré's edition of the Oeuvres Complètes d'Hippocrate (J.B. Baillière et fils, 1861), vol. 9. Letter 10, from the people of Abdera to Hippocrates, begs the physician to come and heal Democritus who is regarded as a sort of village fool, laughing at everything and anything, whether laughable or tragic. In Letter 14, Hippocrates expresses to Damagetus his intention to visit Abdera. In Letter 15, he relates a dream vision in which he encounters Aesculapius: the god tells him he won't need divine help, and turns him over to a beautiful woman who keeps Hippocrates company along the way. Upon taking her leave, she reveals her name: Truth, and remarks that among Abderites there lives another whose name is Opinion. The dream sheds new light on the pleading letter from Abdera's residents who fail to understand Democritus's reason. Letter 17, again addressed to Damagetus, recounts the visit to Abdera and Hippocrates's conversation with Democritus. It turns out that Democritus is in the process of writing a work on madness. All the while he conducts experiments, dissecting animals to examine their bile. As Democritus explains the nature of his laughter – a response to human folly (among other things, he mentions the common conception of happiness, which in turn is built on slavery, greed, and disregard for the earth... – a view which makes him truly modern!) – Hippocrates comes to regard him as a genius rather than a madman. Burton gives a detailed account of this letter a few pages on.

Needless to say, Letter 17 has been a worthwhile digression from Burton's text. The correspondence continues with letters written by Hippocrates and a concluding response.

Diogenes Laertes, in addition to citing anecdotes from other sources, provides a bibliography of Democritus's works – all now lost – which include his Greater and Lesser Diacosmos, or Cosmology.

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[p. 16]

He was much delighted with the studies of husbandry, saith Columella,* and I often find him cited by Constantinus** and others...

* R.B.: Col. lib. 1, cap. 1.  ** Const. lib. de agric. passim.

Lucius Junius Moderatus Columella (4–c.70 CE) was the author of De Re Rustica (12 volumes). 

So far, I'm unable to track down the work on agriculture by Constantine (Constantinus?).

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