In addition to these, there are some Greek writers who have treated of this subject, and who have been already mentioned on the appropriate occasions. Among them, Crateuas, Dionysius, and Metrodorus, adopted a very attractive method of description, though one which has done little more than prove the remarkable difficulties which attended it. It was their plan to delineate the various plants in colours, and then to add in writing a description of the properties which they possessed. Pictures, however, are very apt to mislead, and more particularly where such a number of tints is required, for the imitation of nature with any success; in addition to which, the diversity of copyists from the original paintings, and their comparative degrees of skill, add very considerably to the chances of losing the necessary degree of resemblance to the originals. And then, besides, it is not sufficient to delineate a plant as it appears at one period only, as it presents a different appearance at each of the four seasons of the year.[519] CHAP. 5.—THE FIRST GREEK AUTHORS WHO WROTE UPON PLANTS. Hence it is that other writers have confined themselves to a verbal description of the plants; indeed some of them have not so much as described them even, but have contented themselves for the most part with a bare recital of their names, considering it sufficient if they pointed out their virtues and properties to such as might feel inclined to make further enquiries into the subject. Nor is this a kind of knowledge by any means difficult to obtain; at all events, so far as regards myself, with the exception of a very few, it has been my good fortune to examine them all, aided by the scientific researches of Antonius Castor,[520] who in our time enjoyed the highest reputation for an intimate acquaintance with this branch of knowledge. I had the opportunity of visiting his garden, in which, though he had passed his hundredth year, he cultivated vast numbers of plants with the greatest care. Though he had reached this great age, he had never experienced any bodily ailment, and neither his memory nor his natural vigour had been the least impaired by the lapse of time.