The third of the things we mentioned is fulfilled by laxatives,313 and things that purge the matter of the disease, and that bring comfort to the heart, according to their property; such are, in the case of sanguine humour: cassia fistola, violets, bugloss and borage flowers, to be given along with capon broth or whey of cow's milk after straining. A vein should be opened in this case, provided that it purge the cause,314 the heat, and the spirit; and though this causes greater weakness than any other purging, according to Galen, nevertheless it avails. This is how that should be understood: that purging by blood causes greater weakness than purging by any other medicament.315 Where he speaks of a vein, this
p.151is how that should be understood: when a vein is let excessively it causes greater weakness than any other purging through medicine, for the vein purges every humour and the heat and the spirit, and no other purging does as much; neither is the spirit purged to the same extent by any other purging, except it be a remedy of poison which brings a man to syncope.316 It is of the purging that does not speak of (cause?) syncope317 and does not exhaust the force, that I speak. Indeed, no other purging causes the patient weakness as does letting a vein, because of the suddenness with which the blood comes out, and the heat and the spirit also. For in the other purgings, the humours, the heat and the force are purged more gradually, unless the retentive (?) force be impeded,318 or a laxative be given in excess.