What are Critical Tumours?
They are those that appear all at once in acute Diseases, and terminate them with good or bad Success.
What are Malignant Tumours?
They are those that are always accompany'd with extraordinary and dreadful Symptoms, and whose Consequences are also very dangerous; as the Carbuncle in the Plague.
What are Impostumes or Abcesses, Breakings out and Pustules?
Indeed, it may be affirm'd, that all these kinds of Tumours scarce differ one from another, except in their size or bigness; nevertheless, to speak properly, by the Names of Impostumes or Abcesses are understood gross Tumours that are suppurable, or may be dissolv'd, and by those of Breakings out and Pustules, only simple Pusteal Wheals, or small Tumours, that appear in great Numbers, and which frequently do not continue to Suppuration; some of them consisting of very few Humours, and others altogether of dry Matter.
What difference is there between a Tumour and an Impostume or Abcess?
They differ in this particular, that all Tumours are not Impostumes nor Abcesses; but there is no Impostume nor Abcess that is not a Tumour: As for Example, Wens and Ganglions are Tumours, yet are not Abcesses nor Impostumes; whereas these last are always Tumours in regard that they cause Bunches and Elevations.