The skirret,[1013] too, has had its reputation established by the Emperor Tiberius, who demanded a supply of it every year from Germany. It is at Gelduba,[1014] a fortress situate on the banks of the Rhenus, that the finest are grown; from which it would appear that they thrive best in a cold climate. There is a string running through the whole length of the skirret, and which is drawn out after it is boiled; but still, for all this, a considerable proportion of its natural pungency is retained; indeed, when modified by the addition of honied wine, this is even thought to impart to dishes an additional relish. The larger parsnip has also a similar sting inside, but only when it is a year old. The proper time for sowing the skirret is in the months of February, March, April, August, September, and October. CHAP. 29.—ELECAMPANE. Elecampane[1015] is not so elongated as the preceding roots, but more substantial and more pungent; eaten by itself it is very injurious to the stomach, but when mixed with other condiments of a sweet nature, it is extremely wholesome. There are several methods employed for modifying[1016] its natural acridity and rendering it agreeable to the palate: thus, for instance, when dried it is reduced to a fine flour, and then mixed with some sweet liquid or other, or else it is boiled in vinegar and water, or kept in soak in it; it is also steeped in various other ways, and then mixed with boiled[1017] grape-juice, or else incorporated with honey or raisins, or dates with plenty of meat on them. Other persons, again, have a method of preparing it with quinces, or else sorbs or plums, while sometimes the flavour is varied by the addition of pepper or thyme. This plant is particularly good for weakness of the stomach, and it has acquired a high reputation from the circumstance that Julia[1018] Augusta used to eat it daily. The seed of it is quite useless, as the plant is reproduced, like the reed, from eyes extracted from the root. This vegetable, as well as the skirret and the parsnip, is sown both in spring and autumn, a considerable distance being left between the plants; indeed, for elecampane, a space of no less than three feet is required, as it throws out its shoots to a very considerable distance.[1019] Skirrets, however, are best transplanted. CHAP. 30.—BULBS, SQUILLS, AND ARUM.