Contributions (Volume 4)

This historic book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1911. Not illustrated. Excerpt: ... cuticle of this epidermis is somewhat thicker than that of the lower epidermis. Many of the epidermal elements contain brownish contents. In some the contents appear granular. Numerous bases of sclerotic unicellular hairs are scattered here and there over the surface. A few sclerotic hairs are found and generally occur above the mid-rib and the veins. Each of these is somewhat elevated and surrounded by usually radially arranged cells. Crypts, containing stalked yellowish glandular hairs are numerous. These are generally deeper than those of the lower epidermis. The mesophyll shows a differentiation into a broad upper palisade zone, a middle spongy parenchyme region and a narrow lower palisade layer. The upper palisade zone consists of three layers of columnar shaped cells with variously stained contents. Some of them contain crystals of calcium oxalate which may be in the form of rosettes, monoclinic prisms or crystal sand. Others contain one to several radiating structures which suggest the Actinomyces rosette. The spongy parenchyme region is composed of small celled elements which are irregularly shaped and surround intercellular air spaces. The lower palisade layer is incompletely differentiated and consists of columnar as well as irregular shaped cells, which are loosely arranged. Some of these contain crystals of calcium oxalate. The fibrovascular bundles of the mid-rib and veins run through the spongy parenchyma zone. Those of the stronger veins, as well as that of the mid-rib, are connected with both lower and upper epidermis by hypodermal elements. Those above the bundles are usually lignified. Many of the non-lignified hypodermal elements contain rosettes of calcium oxalate. The vascular bundle of the smaller veins is connected with both the u...