Whereof to speak distinctly: among the Southern constellations two there are which bear the name of the Dog; the one in 16 degrees of latitude, containing on the left thigh a Star of the first magnitude, usually called Procyon or Anticanis, because say some it riseth before the other; which if truly understood, must be restrained unto those habitations, who have elevation of pole above thirty two degrees. Mention thereof there is in _Horace_[SN: Iam Procyon fuerit et stella vesani Leonis.], who seems to mistake or confound the one with the other; and after him in _Galen_, who is willing, the remarkablest Star of the other should be called by this name; because it is the first that ariseth in the constellation; which notwithstanding, to speak strictly, it is not; unless we except one of the third magnitude in the right paw in his own and our elevation, and two more on his head in and beyond the degree of Sixty. [SN: _What the Dog-star is._] A second and more considerable one there is, and neighbour unto the other, in 40 degrees of latitude, containing 18 Stars, whereof that in his mouth of the first magnitude, the _Greeks_ call Σείριος, the _Latines canis major_, and we emphatically the Dog-Star. Now from the rising of this Star, not cosmically, that is, with the Sun, but Heliacally, that is, its emersion from the raies of the Sun, the Ancients computed their canicular daies; concerning which there generally passeth an opinion, that during those daies, all medication or use of physick is to be declined; and the cure committed unto nature. And therefore as though there were any feriation in nature, or justitiums imaginable in professions, whose subject is natural, and under no intermissive, but constant way of mutation; this season is commonly termed the Physitians vacation, and stands so received by most men. Which conceit however general, is not only erroneous, but unnatural, and subsisting upon foundations either false, uncertain, mistaken or misapplied, deserves not of mankind that indubitable assent it findeth.