. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Pleural surface of the human lung, indicating the lobules in shaded outline, and the air-cells a, a. (After Adriani.) as many as 17,790 air-cells are grouped round each terminal bronchus; and that their total number in the lungs amounts to no less than six mi/lions. The dimensions of the air- eel Is given by *, are very much less than those of Rainey and Kolliker. Accord- ing to the former observer, they range from i4oth to Ta'ofcth- °f an incn : those of Car- penter and Kolliker correspond with those of Weber
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Pleural surface of the human lung, indicating the lobules in shaded outline, and the air-cells a, a. (After Adriani.) as many as 17,790 air-cells are grouped round each terminal bronchus; and that their total number in the lungs amounts to no less than six mi/lions. The dimensions of the air- eel Is given by *, are very much less than those of Rainey and Kolliker. Accord- ing to the former observer, they range from i4oth to Ta'ofcth- °f an incn : those of Car- penter and Kolliker correspond with those of Weber already stated. They continue to increase in size from birth to old age, and present in man a greater capacity than in woman. Dr. W. Addison supposed that the air-cells did not exist before birth, that they were mechanically formed by the first act of inspiration, and that the foramina between the cells were really ruptured partitions caused by the pressure of the atmosphere. Fig. Ultimate pulmonary tissue from afcetus three months old. (After Hartinff, quoted by Adriani.) a, a, a, primitive " infundibula," of which the parietes are as yet composed only of minute oval cells (c); b, b, b, elastic tissue occupying the inter- vals between the iufundibula, exhibiting the nuclei of its cells. * Op. cit. It was, however, first proved by Mr. Rainey, and by Professor Hurting more lately, that they exist nearly as perfect in contour before as after birth. Neither the form, the num- ber, nor the disposition of the air-passages and cells can any longer be held as the off- spring of chance, but as the nicely adjusted products of marvellous foresight and design. The preceding statement will enable the reader to understand the sources of the dif- ferences by which the views of different writers upon the structure of the lungs are marked. It is easy to make a" labyrinth/' a "passage," or a "group of vesicles," or " a funnel-shaped ar- rangement
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