1910] Proceedings. 7 



vate, but may be others of the same character, developed from somites 

 above or below. As there is no contact between the neuroblasts and 

 their end organ before differentiation, and as the number which differ- 

 entiates is always decreased by the destruction of the peripheral areas ; 

 moreover, as other investigations have shown that neuroblasts separated 

 from the organism may develop nerve fibers in a drop of lymph, — 

 hence the expressed belief that the stimulus must come from the 

 presence of the metabolic products of the end organs. 



EXPERIMENTS ON AMPHIBIANS. 



Both somites and limb buds were again removed in the amphibians, 

 but the situation is complicated by the fact that regeneration, and 

 redifferentiation always occur. As a consequence no specimen in which 

 all of the end organs of a given nerve were missing was obtained, but 

 by repeated removals the size of the end organs is much reduced and 

 there is always a corresponding decrease in the size of the nerves. 

 Again there is no degeneration, and the obvious conclusion is that the 

 neuroblasts are dependent on the presence of end organs, or the 

 products of the metabolism of end organs for their differentiation. 



The lecture was illustrated with slides made from original photo- 

 graphs. After a spirited discussion participated in by Miss Shorey, 

 Dr. P. H. McGovern, and Dr. P. H. Dernehl, the meeting adjourned. 



Milwaukee, Wis., Nov. 11, 1909. 



Regular meeting of the society. 



President Barth in the chair. 18 members present. Minutes of 

 the last section meeting read and approved. 



The nomination of Mrs. Auguste Reichel, southeast corner Fifth 

 and Sherman Sts., was read and referred to the board of directors for 

 action ; at the subsequent meeting of the board she was elected an 

 active member. A communication from Prof. I. N. Mitchell was read, 

 in which he excused his absence, as the new Normal School was to be 

 eddicated that evening. 



The subject of the evening's discussion was "Nonsexual Schemes 

 of Reproduction." 



Dr. P. H. McGovern opened the discussion by speaking- on 

 Cytogenesis and Reproduction among the Protista. Dr. McGovern out- 

 lined briefly what a cell is, the life history of a cell, and the mechanical 

 relationship of cytoplasm and the cell nucleus in the differentiation of 



