Culture and Preservation of Potatoes. 213 



but I would prefer the tubers grown on peat soil to unripe ones; there is a 

 vigour in these which cannot be attained to, though they are lilted never so 

 green in loamy soil. Mr. Aitken advises to cut over the stems, and leave the 

 potatoes in the ground a considerable time before raising ; but, if the stems are 

 cut so low as to divest them of leaves, they will get little good in the ground; 

 and, if left long, the buds may shoot from the tuber, and weaken them. I 

 would rather advise to have them taken up, and spread on the ground, and 

 turned till the skin gets green, and something approaching to the nature of 

 bark on the stem ; every one in the practice of planting potatoes, will know 

 the superior vigour of those cuts which are taken from the potatoes growing 

 out of the surface and become green ; and we may have the whole of our seed 

 potatoes of the same nature, for a very little trouble. I am of opinion we may 

 err in lifting potatoes too soon, as well as too late; when the food is first de- 

 posited as the future food of the young embryo, whether in tuber or seed, it is 

 deposited in the form of mucilage, which is the least organised state of the sap, 

 and it is subsequently by the deposition of carbon ripened into sugar and farina 

 or starch. Before the starch can become food for the young embryo in the 

 spring, it must again be reduced into the state of mucilage; the first organised 

 state of the food is, therefore, the most suitable nourishment for the young 

 embryo, and hence the superiority of unripe seed corn and potatoes to that 

 which is very much ripened : but the food will not preserve and keep through 

 the winter in this state ; being so low in the state of organisation, it sooner 

 decays, and we may err in lifting too green as well as too ripe. The food in 

 its most highly organised state of farina or starch has been, by some of our 

 best writers on vegetable physiology, compared to particles of mucilage sur- 

 rounded with a shell ; and it requires a good deal of heat and moisture, with in 

 some cases the presence of an alkali, to reduce this starch into mucilage. The 

 earth is the great stomach or laboratory of the food of plants ; and, if we are 

 careful to give it justice by a proper degree of pulverisation, we will have less 

 cause to complain of too ripe seed. Mr. Aitken has given very excellent di- 

 rections for the preparing of the sets, in beds set apart for that purpose, before 

 planting out ; and the lime he recommends to be sprinkled in its quick or 

 powdery state, amongst the sets when preparing, is of great use in their ger- 

 mination ; it furnishes the alkali required, extracts carbon from the starch, gives 

 out heat, and assists powerfully in the solution of the food, as more par- 

 ticularly described in an essay of mine published some years ago in your 

 pages. (See Vol. XIV. p. 71.) 



The paper in the Quarterly Journal has excellent instructions for the pre- 

 servation of potatoes. The principal aim of the writer is to keep the tubers 

 from germinating, by preserving in cool, shaded, dry situations, and by frequent 

 turning; this decreases the heat and moisture, which are the two most 

 essential agents in vegetation. But I am of opinion it will be possible to 

 destroy the vitality of the embryo, without hurting the flour of the potato. 

 Heat and moisture are both necessary to vegetation, but they must be applied 

 at the same time; if we apply heat without moisture to a considerable degree,. 

 we destroy the vitality of the seed altogether, without injuring the farinaceous 

 food contained in the seed or root, so far as domestic purposes are concerned, 

 which was the thing wanted by the Highland Society. Most dealers in seeds, 

 and most nurserymen, are familiar with the effects of kiln-drying seed. When 

 beech mast is collected in England for sowing, it is often immersed in water 

 for the purpose of skimming off" the bad seeds and refuse, which from their 

 lightness rise to the top ; and it is then spread on the top of a malt-kiln to 

 dry before sending off. We have had this seed frequently sown in the nursery 

 grounds, and exposed to all the rains that fell for six months, without vege- 

 tating, and, at the end of this time, as white and full in the kernel as whea 

 sown. The seed of larch fir, being difficult to extract from the cone, is often 

 put on the kiln head, and we have often the same complaints of it. The seed 

 when cut is as full of flour as before, only, if magnified, it is deficient in 

 moisture ; the substance of the food has lost its waxy appearance, but is still 



