A small piece of the lining epithelium of the trachea with its underlying cartilage was also placed in the lymph gland. The epithelium grew, and covered over the wounded surface, forming over it only a single layer of cells. The old many-layered epithelium also became arranged in a single layer. The wax glands, found in the inguinal folds of the rabbit, were also transplanted. The gland is composed of closed, compressed alveoli, surrounded by large, polygonal, clear cells. Small pieces of a gland, transplanted upon the lymph gland, underwent characteristic changes. The cells of the alveoli were changed into a stratified epithelium; and broken-down cells, and wax, were found in the interior of the alveoli. The central alveoli underwent the greatest change, while some of the peripheral alveoli that were in contact with the lymph gland remained unchanged. It seems that the difference is due to the better nourishment of the outer alveoli. After several months the alveoli swell up and degenerate. Transplanted pieces of the salivary glands also change, the alveoli producing a lining epithelium like that of the transplanted wax gland. The same change was observed in a piece of a salivary gland transplanted in the body cavity. Small pieces of the liver were cut off and placed in the lymph gland. They did not always grow as well as did the preceding tissues, but often went to pieces. If they healed, the liver tissue often remained unchanged for several weeks. After two or three weeks connective tissue appeared between the peripheral liver cells, separating the cells from each other. The cells grew smaller, their protoplasm disappeared, and they at last disintegrated. Pieces of the gall duct behaved differently. They sometimes showed active growth, leading to the development of numerous branched canals.[86] Pieces of the kidney, when transplanted, suffered a great change, and were subsequently absorbed. Transplanted pieces of a testis also changed. After six days, Sertoli’s cells and the spermatozoa disappeared. A kind of indifferent cell remained, characterized by clear protoplasm and by a large nucleus. After seventeen days further changes were observed, and later the pieces were completely absorbed. Pieces of the ovary rapidly disappeared, leaving only a mass of interstitial connective tissue. The connective tissue underwent, in all the transplanted pieces, characteristic changes. The tissue became less dense, the protoplasm and nucleus of each cell enlarged. The cells multiplied, but only very slowly. These changes took place after one or two days. After a month or two the cells became more compact, their processes more numerous, and the nucleus small and long. Later degeneration set in.