No. 2.] CHANGES IN NERVE CELLS. 103 



The evidence for this last point is, however, questioned by 

 Langley, who strongly advocates the opposite view, that after 

 secretion, and in fact during secretion, the same cells refill with 

 protoplasm and zymogen granules, and so on indefinitely. The 

 facts thought by Heidenhain to indicate cell-renewal are given 

 another interpretation by Langley {34, p. 6j6). He also ques- 

 tions whether the nucleus actually swells, and maintains that it 

 simply appears larger in proportion to the greatly shrunken 

 cells. In the same paper (p. 698) Langley emphasizes another 

 point of great importance to us, viz. that processes of rest and 

 activity, anabolism and katabolism, go on in the same cells at the 

 same time. Hence the appearance of a cell at any time depends 

 upon whether one or the other process is in ascendency. This 

 may account for the fact that one observer (62) has found that 

 the cells of the gastric glands in the frog increase in size for 

 twelve to eighteen hours after feeding, and then gradually 

 resume their normal size. This observation, however, stands 

 alone, and during his twelve years of close study Langley has 

 seen nothing to confirm it. In general, Langley makes little of 

 changes of the nucleus. 



Seiller ij6), in a special study of mucous cells, by most 

 recent methods, supports the view of Langley, that goblet cells 

 do not perish in secretion, but regenerate their protoplasm. 



Great prominence is given to the action of the nucleus by 

 Ogata (60) in his work upon pancreas secretion. A body with 

 peculiar staining properties, plasmasoma, arises in the nucleus, 

 and migrating out into the protoplasm may give rise to a mass 

 of zymogen granules ; or it may develop into a new nucleus, 

 form a new cell about it, and then produce zymogen gran- 

 ules. That is, the process is chiefly reproductive in character. 

 There may be a stable mechanism in the cells which can manu- 

 facture zymogen granules, but under special stimulation this is 

 not sufficient (p. 430). Here, moreover, the reproductive proc- 

 ess is different from ordinary cell-division, in which both cells 

 live ; the old cells in this case dying away. It is different also 

 from the fact that there is nothing comparable with karyo- 

 kinesis ; nor does the formation and migration of plasmasoma 

 resemble direct nuclear division. Kiihne and Lea (33) saw 

 granules in living cells of triton's pancreas streaming from the 

 neighborhood of the nucleus toward the lumen (21, p. 203); 



