THE STKUCTUllE OF CIIRO.MOPIIILE CELLS UF THE .NERVOUS SYSTEM. 



By E. V. CowDRv. 



INTRODUCTION. 



It has long been known that certain pecuhar nerve-cells, well characterized 

 by their structural appearance, occur in the normal human brain, and indeed in the 

 brains of all the vertebrates which have been examined. In fixed preparations they 

 are slightly shrunken, they stain deeply with both acid and basic dyes, and their 

 nuclei are obscure and hard to define. Flesch (1887, p. 196) called them "chro- 

 mophile" cells. Nissl (1896, p. 1154) thought at first that they were artefacts of 

 some sort, but Cajal (1909, p. 210) and others brought forward strong evidence 

 against this view. Cajal (1909, p. 211) concluded that they were resting cells. 

 On the other hand, in the light of DoUey's (1910, p. 333) work, they would seem to 

 be in the initial stages of fatigue, as evidenced by the increase in the amount of 

 NissI substance in them and by their obscure, deeply-staining nuclei. Our knowl- 

 edge of their structure is incomplete so far as the mitochondria and the canalicular 

 apparatus are concerned. Busacca Archimede (1913, p. 332), alone, has observed 

 that the mitochondria in certain cells in the brain of Testudo grceca stain particu- 

 larly intensely with iron hematoxylin, and in some cases seem to lose their definite 

 outlines and to form homogeneous masses. Rina Monti (1915, p. 39) has made 

 a comprehensive study of the canalicular apparatus ("apparati di Golgi") in 

 nerve-cells, but she does not mention cells in the chromophilic condition. I shall 

 consequently venture to present in this paper my observations on these two 

 structures in the chromophile cells in the brain of the white mouse. 



MATERIAL AND METHODS. 



White mice were employed because they are the smallest mammals which can be 

 conveniently used in the laboratory for experimental purposes. The small size of 

 their nervous system permits the study of the distribution and the arrangement of 

 chromojihile cells in serial sections. All the mice were of known age and care was 

 taken that they were perfectly normal. 



A modification of the methods of Altmann (1890, p. 27), Galeotti (1895, p. 

 466), Regaud (1910, p. 296), Bensley (1911, p. 309), and Shirokogoroff (1913, p. 

 523) was devised for the study of mitochondria. The method has many advantages. 

 In the first jjlace, the use of a mixture of formalin and potassium bichromate as a 

 fixative (Regaud) gives a much more uniform preservation of mitochondria than the 

 osmic acid containing fixatives in general use. The application of the fixative by 



'The work was aided by the Departmoiit of Embryology of the Carnegie Institution of Washington, and part of 

 it was done at the Marine Biological Lalx)ratory. Woods Hole, Massachusetts, where, throujih the kindni'ss of the Director. 

 Dr. T.illie. a room was placed at mv disposal. 



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