Histological Studies on the Respiratory Portions of the Lungs of Cetacea

The histology of the lungs of aquatic mammals have been studied by a number of previous authors, FIEBIGER (1916), NEUVILLE (1928), WISLOCKI (1929), BELANGER (1940) etc. In the present paper my own histological studies on the pulmonary divisions from the bronchoile to the air spaces in several kinds of the cetacea will be mentioned. The whales treated here are three species of Odontoceti, Prodelphinus caeruleoalbus MEYEN, Berardius bairdii STEJNEGER and Catodon physeter L. (Sperm whale) and three kinds of Mystacoceti, Balaenoptera physalus L. (Fin whale), Balaenoptera borealis LESSON (Sei whale) and Balaenoptera musculus L. (Blue whale). The Prodelphinus caeruleo-albus was caught near the coast of Izu Peninsula, the Berardius near Shirahama in Tiba Prefecture and the Sei whale near Kinkazan in Miyagi Prefecture, while the Sperm, the Fin and the Blue whale were all captured by the boats of NisshinMaru in the Antarctic Ocean. Blocks cut from the lungs were fixed in 10% formalin, embedded then in celloidin and made into serial sections of 20 μ and 100 μ thickness. The 20 μ sections were stained alternately with haematoxylin' eosin and WEIGERT's resorcin-fuchsin, while the 100 μ sections were stained only by the latter method for the study of elastic fibers.