One of these varieties—the CROCODES PACCIANUM—received its name from Paccius, a celebrated Roman medical practitioner, who either invented this special collyrium, or brought it into repute. Paccius, who lived about the commencement of the Christian era, is said to have amassed a fortune by the sale of a secret nostrum. At his death he bequeathed the prescription for it to the Emperor Tiberius, who placed a copy of it in the various public libraries.[461] In the list of his ophthalmic medicines, Galen gives formulæ for various collyria invented by Paccius, such as the “_Sphragis Paccii_,”[462] “_Asclepiadeum Paccii_,”[463] “_Collyrium_ ex terra Samia _Paccii Ophthalmici_ ad affectus intensos (επιτεταμενας διαθεσεις).”[464] Galen does not give any recipe for the _Crocodes_ of Paccius; but it was evidently a collyrium duly esteemed at the time in which he wrote; for, in his chapter on ulcers of the eyes, he specially names the “CROCODES PACCIANUM,”[465] and recommends its use in cases in which the accompanying inflammation has already ceased, and at the stage when a stimulating application becomes necessary. The other variety of crocodes used by Sedatus is the CROCODES DIALEPIDOS. A formula for _Dialepidos_ is given by Marcellus,[466] with the crocus as the first ingredient mentioned in its composition. The _Dialepidos_ derived its name from its containing the scales—(λεπιδες) of burnt copper, or the black peroxide of that metal,—a preparation which Dioscorides (lib. v. cap. 89) describes as useful in eye-diseases; and which Galen declares to be a “medicamentum multo utilissimum,” vol. xii. p. 223. SECTION IV. STAMP NO. III.—CONTAINED IN THE BRITISH MUSEUM. A second Roman medicine-stamp is (as I have already stated, p. 244) contained in the British Museum. The stone is small and broken, and only engraved on one side (see Plate I., No. III.) The inscription does not include, as usual, the name of the oculist who possessed and employed it. The lettering on this stamp is very distinct, except in one particular. It is doubtful whether the third last letter is intended for an “L,” or stands, as suggested by Mr. Way, for an “I,” with a period-point after it, thus—“I.” An inspection of the stamp itself has impressed me with the belief, that the doubtful letter is truly an “L;” and if so, the inscription would run:— COLLYR. P. CLOC. Or, to read it in an extended form, COLLYR_ium_ P_ost_ C_a_L_iginem_ OC_ulorum_—_Collyrium for blindness of the eyes._ And I may observe that several of the prescriptions found on these medicine-stamps are collyria professing to be useful against and after (_ad_ and _post_) _caliginem_. But if the doubtful letter is an “I,” and not an L, then the inscription, when extended, may be read as follows:—COLLYR_ium_ P_ost_ CI_catrices_ OC_ulorum_, or, “_Collyrium after cicatrices of the eyes._”