The garden plants, too, like the rest of the vegetable productions, are subject to certain maladies. Thus, for[1] instance, ocimum, when old, degenerates into wild thyme, and sisymbrium[2] into mint, while the seed of an old cabbage produces rape, and vice versâ. Cummin, too, if not kept well hoed, is killed by hæmodorum,[3] a plant with a single stalk, a root si- milar to a bulb in appearance, and never found except in a thin, meagre soil. Besides this, cummin is liable to a peculiar disease of its own, the scab:[4] ocimum, too, turns pale at the rising of the Dog-star. All plants, indeed, will turn of a yellow complexion on the approach of a woman who has the menstrual discharge[5] upon her.

There are various kinds of insects,[6] too, that breed upon the garden plants—fleas, for instance, upon turnips, and caterpillars and maggots upon radishes, as well as lettuces and cabbages; besides which, the last two are exposed to the attacks of slugs and snails. The leek, too, is infested with peculiar insects of its own; which may very easily be taken, however, by laying dung upon the plants, the insects being in the habit of burrowing in it. Sabinus Tiro says, in his book entitled "Cepurica,"[7] which he dedicated to Mæcenas, that it is not advisable to touch rue, cunila, mint, or ocimum with any implement of iron.