The larva of the Cerambyx cerdo, as well as the ant, Formica rufa L. hormigas, destroys the fine cork with their numerous borings and galleries. Jaspered (Jasperado) is the name by which is known one of the defects of the cork which reduces it greatly in value and as far as can be learned comes from the tree itself. The porosity of cork is greatly increased by the presence of cork-meal, resulting from the disintegration of the Sclerenchyma, or stone cells, which penetrate the cork fiber and falling to a powder facilitate the entrance of infection.[16] [16] _Scientific American_, 1906. STRIPPING [17] The corkwood or cork of commerce is the external part or “periderm” of the cork-oak; and when it has attained a diameter of approximately 12.7 centimeters or the tree measures forty centimeters in circumference according to the Spanish governmental regulations, which the tree does usually by the time it is twenty years old, the bark may be removed. The stripping generally takes place during July and August, and it is a process which demands skill and care, if injury to the bark is to be avoided. In Algeria the French strippers sometimes use crescent-shaped saws, but under the usual Spanish method a hatchet, with a long handle, is the only implement employed. The bark is cut clear through, around the base of the tree, and a similar incision is made around the trunk, just below the spring of the main branches; the two incisions are then connected by one or two longitudinal cuts, following, so far as possible, the deepest of the natural cracks in the bark. Inserting the wedge-shaped handle, the tree’s covering is then pried off. The larger branches are stripped in the same manner, yielding, generally, a finer grade of cork than that of the trunk. The thickness of the bark ranges from 1.27 centimeters to 6.85 centimeters, while the yield also varies greatly from twenty to 75 kilograms[18] per tree, depending upon its size and age. After the first stripping the tree is left in the juvenescent state to regenerate, and great care must be taken in the stripping not to injure the inner skin or epidermis at any stage of the process, for the life of the tree depends upon its proper preservation, for if injured at any point, growth there ceases and the spot remains forever afterward scarred and uncovered. It is also necessary to avoid stripping during the prevalence of a sirocco, which would dry the inner skin too rapidly and therefore exclude all further formation of cork. [17] Armstrong Cork Co.’s pamphlet. [18] Kilogram = 2.205 pounds.