41. Of Sensation, and of Memory. iv. 6. 42. Of the Kinds of Existence, First. vi. 1. 43. Of the Kinds of Existence, Second. vi. 2. 44. Of the Kinds of Existence, Third. vi. 3. 45. Of Eternity and Time. iii. 7. Plotinos wrote these twenty-four books during the six years I spent with him; as subjects he would take the problems that happened to come up, and which we have indicated by the titles of these books. These twenty-four books, joined to the twenty-one Plotinos had written before I came to him, make forty-five. VI. PLOTINOS'S BOOKS OF THE THIRD PERIOD (THE EUSTOCHIAN PERIOD). While I was in Sicily, where I went in the fifteenth year of the reign of Gallienus, he wrote five new books that he sent me: 46. Of Happiness. i. 4. 47. Of Providence, First. iii. 2. 48. Of Providence, Second. iii. 3. 49. Of the Hypostases that Act as Means of Knowledge, and of the Transcendent. v. 3. 50. Of Love. iii. 5. These books he sent me in the last year of the reign of Claudius II, and at the beginning of the second. Shortly before dying, he sent me the following four books: 51. Of the Nature of Evils. i. 8. 52. Of the Influence of the Stars. ii. 3. 53. What is the Animal? What is Man? i. 1. 54. Of the First Good (or, of Happiness). i. 7. These nine books, with the forty-five previously written, make in all fifty-four. Some were composed during the youth of the author, others when in his bloom, and finally the last, when his body was already seriously weakened; and they betray his condition while writing them. The twenty-one first books seem to indicate a spirit which does not yet possess all its vigor and firmness. Those that he wrote during the middle of his life, show that his genius was then in its full form. These twenty-four books may be considered to be perfect, with the exception of a few passages. The last nine are less powerful than the others; and of these nine, the last four are the weakest. VII. VARIOUS DISCIPLES OF PLOTINOS. Plotinos had a great number of auditors and disciples, who were attracted to his courses by love of philosophy. Among this number was Amelius of Etruria, whose true name was Gentilianus. He did indeed insist that in his name the letter "l" should be replaced by "r," so that his name should read "Amerius," from "ameria" (meaning indivisibility, though Suidas states that it was derived from the town of Ameria, in the province of Umbria), and not Amelius, from "amellia" (negligence).