They are these, _viz._ to make choice of a proper Vessel; not to open any at all Adventures; not to let Blood without necessity, nor {205} without the Advice of a Physician; whose Office it is to determine the Seasons or Times convenient for that purpose; as that of Intermission in an Intermitting Fever; that of Cooling in the Summer; and that of Noon-tide in the Winter; and lastly, to take away different quantities of Blood; for in the Heat of Summer they ought to be lesser, and greater in the Winter. _What are the Accidents of Phlebotomy?_ They are an Impostume, a _Rhombus_, an _Echymosis_, an _Aneurism_, Lipothymy, Swooning, and a Convulsion. _What is a _Rhombus_?_ It is a small Tumour of the Blood which happens in the place where the Operation is perform'd either by making the Orifice too small, or larger than the Capaciousness of the Vessel will admit. The _Rhombus_ is cur'd by laying upon it a Bolster dipt in fair Water, between the Folds of which must be put a little Salt, to dissolve and prevent the Suppuration. _How may it be perceiv'd that an Artery hath been prickt or open'd in letting Blood?_ The Puncture of an Artery produceth an Aneurism; and the Opening of it causeth a Flux of Vermilion Colour'd Blood, which issueth forth in abundance, and by Leaps. _Are the Leaps which the Blood makes in running, a certain Sign that it comes from an Artery?_ No, because it may so happen, that the _Basilick_ Vein lies directly upon an Artery, the beating of which may cause the Blood of the {206} _Basilica_ to run out leaping: Therefore these three Circumstances ought to be consider'd jointly, that is to say, the Vermilion Colour, the great quantity and the Leaps, in order to be assur'd that the Blood proceeds from an Artery. _How may it be discover'd that a Tendon hath been hurt in letting Blood?_ It is known when in opening the _Median_ Vein, the end of the Lancet hath met with some Resistance; when the Patient hath felt great Pain, and afterward when the Tendon apparently begins to be puff'd up, and the Arm to swell. A Remedy may be apply'd to this Accident thus; after having finish'd the Operation, a Bolster steep'd in _Oxycratum_ is to be laid upon the Vessel, a proper Bandage is to be made, and the Arm must be wrapt up in a Scarf: If the Inflammation that ariseth in the Part be follow'd with Suppuration, it must be dress'd with a small Tent; and if the Suppuration be considerable, it is necessary to dilate the Wound, and to make use of Oil of Eggs and Brandy, or _Arcæus_'s Liniment, with a good Digestive; as also to apply _Emplastrum Ceratum_; to make an Embrocation on the Arm with Oil of Roses; and to dip the Bolsters in _Oxycratum_ to cover the whole Part. _Is it not to be fear'd that some Nerve may be wounded in letting Blood?_ No, they lie so deep that they cannot be touch'd. _Under what Vein is the Artery of the Arm?_ It is usually situated under the _Basilica_. {207}