GROWTH OF THE INNER EAR OF ALBINO RAT 



95 



In table 67 are given the values for the volume of the cell 

 bodies in the (1) inner and (3) outer hair cells separately and 

 the weighted volume of both cells (in the radial section of the 

 rat cochlea we see one row of inner and three rows of outer 

 hair cells), according to age. 



TABLE 67 



Average volumes of the inner and outer hair cells — in cubic micra 



{charts S3 to 87) 



AGE 



days 



BODY 

 WGHt 



3 



6 



9 



12 



15 



20 



Av. 11 



25 

 50 

 100 

 150 

 257 

 366 

 546 



Av. 213 



gms 

 5 



8 

 11 

 10 

 13 

 13 

 29 



14 



INNER HAIR CELL 



Turns of the cochlea — M 3 



I 



1255 



1457 

 1374 

 1451 

 1553 

 1598 

 1627 



1510 



36 

 59 

 112 

 183 

 137 

 181 

 255 



138 



1540 

 1497 

 1353 

 1362 

 1345 

 1290 

 1266 



1379 



II 



982 



1367 

 1451 

 1734 

 1812 

 1618 

 1764 



1624 



1655 

 1611 

 1550 

 1497 

 1524 

 1561 

 1486 



1555 



ill 



832 



1206 

 1549 

 1994 

 1910 

 1902 

 1972 



1756 



1909 

 1821 

 1744 

 16S3 

 1738 

 1817 

 1772 



1783 



IV 



631 



913 

 1221 

 2013 



2157 

 2128 

 2189 



1770 



1995 

 1924 

 2018 

 1917 

 1976 

 2297 

 2257 



2055 



Average 



925 641 



1236 

 1399 



1798 

 1858 

 1812 



1888 



1665 



1775 

 1713 

 1666 

 1615 

 1646 

 1741 

 1695 



1693 



OUTER HAIR CELL 



Turns of the cochlea — j" 3 



767 

 1047 

 914 

 818 

 815 

 894 



876 



834 

 805 

 837 

 832 

 873 

 893 

 831 



844 



II 



626 



928 

 967 

 1308 

 1210 

 1178 

 1215 

 Fl34 



1243 

 1204 

 1306 

 1150 

 1230 

 1239 

 1336 



1244 



ill 



505 



867 

 1053 

 1459 

 1602 

 1595 

 1606 

 1364 



1539 

 1580 

 1510 

 1803 

 1555 

 1651 

 1650 



1613 



IV 



359 



571 

 800 



14; 8 



1499 

 1559 

 1960 



1303 



1702 

 1906 

 1737 

 1917 

 1927 

 1844 

 1839 



1839 



Average 



533 



783 

 967 

 1277 

 1282 

 1287 

 1419 



1169 



1330 

 1374 

 1348 

 1426 

 1396 

 1407 

 1414 



1385 



WEIGHTD 

 AVERAGE 

 VOLUME 



631 



896 

 1075 

 1407 

 1426 

 1418 

 1536 



1293 



1441 

 1459 

 1428 

 1473 

 1459 

 1491 

 1484 



1462 



At first we shall consider the weighted volume for the cell 

 bodies of the inner and outer hair cells combined (chart 33). 

 As table 67 shows, the volume increases continuously to the full 

 size at twenty days. From one to twelve days the increase is 

 rapid, and after that the volumes are about the same, though 

 somewhat fluctuating. The ratios show this relation clearly. 



