1 82 R. R. BENSLEY. 



The method of Kopsch has been exploited in particular by 

 Misch ('03), and von Bergen ('04). The former found that the 

 apparatus was not present in all cells and that in some cells it 

 presented itself in the form of fragments, or of rows of granules. 

 He found, moreover, in agreement with Golgi and Kopsch that 

 the network never communicated with the surface of the cell, 

 nor did it penetrate the nucleus. Von Bergen's studies extended 

 to a very large category of cells ranging from wander cells to 

 nerve cells. To show how general these structures are in animal 

 cells a list of the elements in which von Bergen obtained positive 

 results would have considerable interest. In addition to nerve 

 cells he found a reticular apparatus in the following elements: 

 prostate epithelium, pancreas cells, demilunes and mucous cells 

 of the submaxillary gland of the cat, glandular epithelium from 

 the trachea, chief cells of the fundus glands of the stomach, 

 ciliated epithelium of the trachea, epithelium of the sweat glands, 

 wander cells and many leucocytes, fixed connective tissue cells, 

 cartilage cells, endothelium, smooth muscle, interstitial cells of 

 the testis. The wide range of these observations taken in con- 

 nection with the observations of Golgi and Cajal and their pupils 

 indicate that the reticular apparatus is by no means a structure 

 confined to a single cell category but is a cell organ of almost if 

 not quite universal occurrence in the. protoplasm of animal cells. 



Before passing to a review of the investigations that have 

 been made from the standpoint of the canalicular apparatus of 

 Holmgren and others it may be of interest to refer briefly to the 

 studies of Golgi on the development of the reticular apparatus. 

 In the nerve cells of the foetal calves of two or three months, he 

 found the apparatus greatly reduced, often consisting of but a 

 single fiber, with short branches running in various directions. In 

 these cells the apparatus has a distinctly excentric position at 

 one pole of the nucleus. In the new-born animal the net often 

 extended around the nucleus, but left the perinuclear zone as 

 well as the peripheral protoplasmic zone entirely free of such 

 fibers. In old animals the apparatus was sometimes broken 

 up into peculiar island-like fragments which however were con- 

 nected with one another by single fibers. These observations 

 suggest strongly that the apparatus constitutes a unit in its ori- 

 gin and developmental history. 



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