A ganglion is a round tumour of a tendon, arising from a blow or violent exercise, being formed most frequently about the wrists, ankles, and the parts about a joint which are much moved, but likewise in the other parts. It is attended with a swelling, which is free from discoloration, unyielding, and without pain, but if strongly pressed upon it has a dull feeling. It is not deep-seated, but takes its origin under the skin, and may be moved laterally, but cannot by any means be forced forwards or backwards. Those then which form in the legs, arms, and extremities it is not safe to cut out, for there is danger lest the part be mutilated. But those about the head or forehead we operate upon by dividing the skin with a scalpel, and if the tumours be small, seizing them with a flesh forceps and cutting them out by the roots. But if they are larger, we transfix them with hooks, and remove them by dissecting them from the skin, and uniting the lips with sutures, complete the cure by the treatment applicable to fresh wounds. * * * * * COMMENTARY. We have treated of ganglion in the Fourth Book, and mentioned the principal authorities on the subject. Hippocrates and most of the others forbid ganglia to be opened. The hard tumour on the head, to which likewise he applies the name, may safely be removed in the manner described by our author. Albucasis repeats his directions. (Chirurg. ii, 50.) Haly Abbas recommends discutients at first, and if these have not the desired effect we are to strike the tumour with a hard body so as to break its cyst. (ix, 10.) Rhases recommends striking the tumour with a hammer, binding a piece of lead on it, and excision. When excision is practised he directs us to take pains to extirpate the cyst or tunic which surrounds it. (Cont. xxviii.) SECT. XL.—ON VENESECTION.