ZOOLOaY AND BOTANY, MICKOSCOPY, ETC. 713 



cliemical reactions of nerve-cells. (1) The specific cells of the nervous 

 system are distinguishable, not only by their morphological characters 

 and the number of their processes, but also by their chemical reactions. 

 (2) The chemical differences of the nerve-cells are demonstrable by 

 their varied characteristics in the living tissue, by their various reactions 

 to alkaline tests, by their variable amount of free oxygen present, and 

 by their unequal reducing powers. ( 3) The chemical difference is a 

 function of the protoplasm, and not of the contained granula. (4) The 

 chemical characters of the protoplasm of nerve-cells are different from 

 those of all other cells in the body. The only excej^tions are those 

 chromophilous cells which from the nature of their nuclei appear to be 

 in process of degeneration. (5) The chromophilous character is seen in 

 the younger cells only next the nucleus, and gradually extends over the 

 cell. The differences vary with age. The smallest nerve-cells are 

 intermediate between chromophilous and chromophobic cells. (6) The 

 chromophilous or chromophobic character depends on the functional 

 import of the cells. The demonstration of change in chemical con- 

 stitution in association with difference of function is the most important 

 result. 



Frl. Anna Kotlarewsky * has continued the investigations of Prof. 

 M. Flesch and Frl. Koneff on the micro-chemistry of the nerve-cells in 

 peripheral ganglia. Her observations were made in part on living, in 

 part on hardened tissues. As the result of the former, it is shown that 

 the chromophilous and chromophobic cells of the spinal ganglia in their 

 living state differ widely in their chemical state and in the intensity of 

 their metabolism. It seems most probable that the chromophilous cells 

 have a stronger alkalinity and a greater proportion of oxygen than the 

 chromophobic elements. The latter exhibit less reducing power than 

 the former. 



Observations made on hardened nerve-cells led the author to the 

 result that under all conditions the different forms of nerve-cells may 

 exhibit their differences of constitution, that hardening in alkaline media 

 is the best condition for the demonstration of the chemical differences 

 in the body of the cell, and that the chromophilous cells show, without 

 exception, a stronger aflBLnity for metallic solutions than do the chromo- 

 phobic elements. 



The results of staining went to show that the nerve-cells have dis- 

 tribution of cellular substance different from that of the other tissues. 

 The nucleus is poor in chromatin, and the protoplasm is readily stained 

 by various reagents. It seems also possible to determine various 

 metabolic or functional stages by fixing the corresponding morphological 

 conditions. 



Histology of the Ovary.t— Prof. J. Janosik has investigated the 

 structure of the ovary in various vertebrates. He finds that the egg and 

 the follicular epithelium have their origin in the superficial epithelium 

 of the ovary. The structures described by KoUiker and Mihalkovics do 

 not develope into follicles ; they are merely modified medullary cords 

 which have the appearance of follicles. They were seen in all the forms, 

 including man, which he examined, but they do not appear always at the 

 same stage, nor do they all attain the same grade of development. In all 



* MT, Naturf. Gesell. Bern, 1888, pp. 3-23. 



t SB. K. Akad. Wiss. Wieu, scvi. (1888) pp. 172-98 (1 pi.). 



