90 ANATOMY 



size of these cells rather than with a modification, based on 

 age, in the response of the cells to the reagents used in their 

 preparation. 



Olfactory bulbs : number of cells. As an average of three 

 counts, Holt ('17) found in one olfactory bulb of the albino 

 rat, 62-134 days of age, the number of small cells in the molec- 

 ular layer to be 1,000,000 2 per cent, and as an average of 

 thirteen counts the number of mitral cells to be 76,750. The 

 range of these counts was from 70,625 to 83,974 with a- 4564, 

 and P.E.M. 855. 



The diameters of the Purkinje cells have been studied by 

 Addison, '11. 



The Albinos were from the stock colony of The Wistar In- 

 stitute, reared on the scrap diet. The cerebellum was fixed in 

 Ohlmacher's solution (King, '10) imbedded in paraffin and 

 stained with carbol-thionine and acid fuchsin. The values for 

 the respective diameters given in table 50 are in each instance 

 averages of ten measurements from the largest cells found in 

 equivalent areas at the several ages. The measurements stop 

 at 20 days of age. After this age there is but little change in 

 the diameters of the largest cells. 



(2) Spinal cord. For the weight of the spinal cord see Chapter 

 7, p. 206, and table 144. For the percentage of water see Chap- 

 ter 8, p. 308, and table 157. For the chemical composition 

 see Chapter 9, and table 178. Cell division in the spinal 

 cord after birth has been studied by Hamilton, '01, see table 

 43 and Allen ('12) see table 44. 



Peripheral Cranio-spinal nerves. Cranial nerves: Third 

 nerve: Boughton ('06) studied the increase with age (body 

 weight) in the number of myelinated fibers in the oculomotor 

 nerve in the albino rat and measured the areas of the entire 

 fiber and the axis in osmic preparations. The results are given 

 in table 51. 



Fifth cranial nerve. Nittono ('20) followed the growth in 

 size of the neurons composing the sensory division of the tri- 



