During recent years our knowledge of nasal physiology has been considerably increased. This is due in great measure to refinements in microscopic and histologic studies of the cilia making it possible to observe and measure their size. When Leeuwenhoek made the first microscope, about 1650, he opened up an entirely new field and described his findings of ciliary movement in certain minute animals.In the lower forms of aquatic animal life cilia playa most important part, both as a means of locomotion and in the ingestion of food. These microscopic organisms are dependent on the cilia over their body surface to move them about in the water. This movement is necessarily slow, as it is not influenced by muscular action. In the higher vertebrates, including man, with greater body metabolism, active motion and the swallowing of food is carried out by powerful muscular action, and from that point of view cilia playa secondary rOle. This is well shown in studying the growth and transition of the tadpole to the frog. Before the embryo is hatched from the egg, cilia appear and by the time it reaches 3 mm. in length the whole surface is covered with cilia. Definite currents are produced, which were described and carefully mapped out by Assheton 1 51 years ago. These are constant and extend from the head over the back, lateral and ventral surfaces toward the tail. "By the time the tadpole is 6 to 7 mm. long, its cilia are capable of moving the organism over the surface of a flat glass vessel at the rate of 1 mm. in four to seven seconds. As the embryo increases in size and approaches the frog stage, the ciliary currents become less powerful" and finally disappear

Comparative anatomic studies of the bony labyrinths of humans and those of a full grown pony, zebra, grizzly bear, seal and domestic cow were performed. Fusible metal was injected into the labyrinths and the resultant casts were then measured. The similarities and differences were noted and discussed.

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