262 SUMMARY^OF CURRENT RESEARCHES RELATING TO 



These vary in number from three to twelve. The authors believe that 

 their distribution proves that they are certainly of nervous nature, and 

 that their function is to conduct to a cell stimuli either from the col- 

 laterals or from another cell-body. The neurites arise from the body 

 of a nerve-cell or from the dendrites of a cell. 



Hypophysis Cerebri in Man.* — Waldemar Thorn has sectioned a 

 series of brains in which the hypophysis was sometimes normal and 

 sometimes abnormal, and finds that cyanophil and eosinophil cells are 

 normal constituents. The so-called chief cells (Haujptzellen), he divides 

 into feebly cyanophil, feebly eosinophil, and "chromophobe" cells which 

 take up no stain. The secretion which fills the inter-follicular spaces is 

 produced as follows. The strongly chromophil cells produce a chromo- 

 phil secretion in the form of very fine granules. The cell-boundaries 

 become indistinct, the nucleus travels to the periphery, the granules leave 

 the cell and mingle with a non-staining secretion produced by the 

 chromophobe elements. This mixture either diffuses through the inem- 

 brana propria, or the marginal cells degenerate and the membrana 

 propria disappears. In pathological conditions the amount of colloidal 

 substance so produced may be greatly increased. 



Nerves of Hard Palate in Mammalia.t — Dr. Eugen Botezat has in- 

 vestigated this subject, especially in the domestic cat. He finds that the 

 nerve-endings can be divided into two sets, those which end in taste- 

 menisci, and those which end in terminal swellings. The fibrils which 

 lead to these two kinds of nerve-endings arise from the same branches, 

 and there is no marked difference in function. The taste-menisci are 

 present everywhere where Merkel's taste-cells occur, and these are 

 arranged according to the shape of the papillae. The taste-menisci, as 

 their position shows, react to pressure, while the terminal swellings, 

 which penetiate into the epithelium sometimes as far as the stratum 

 corneum, are specially sensitive to chemical stimuli and to temperature,, 

 as well as to pressure. Of the nerve-endings with terminal swellings 

 several modifications exist, those most characteristic of the cat being the 

 brush, or pencil endings, found in the large papillae. 



Primitive Fibrillae of Retina.J — Gustav Embden has applied Bethe's 

 method to the study of the nerve-cells of the retina, but has not been 

 very successful in demonstrating primitive fibrillae within the cells. The 

 material was chiefly the eye of the horse. He was most successful in 

 staining the horizontal cells and their prolongations, and found both in 

 the cell-body and in the processes very fine primitive fibrillae clearly 

 differentiated. In some cases he succeeded in demonstrating the anasto- 

 moses of the processes of adjacent cells, and then found that the primitive 

 fibrillae were continuous from the process of one cell to that of another. 

 He was also successful in the large ganglion-cells of the ganglion nervi 

 optici and their processes, obtaining in some cases clear preparations of 

 the fibrillae. In some cases these fibrillae passed from a cell-prolonga- 

 tion to the axis-cylinder, in other cases from one process to another of 

 the same cell. 



'* Arch. Mikr. Amtt., lvii. (1901) pp. 632-52 (2 figs.). 

 > Zeitschr. wiss. ZooL, lxvi. (1901) pp. 429-443 (2 pis. and 1 fig.). 

 \ Arch. Mikr. Anat., lvii. (1901) pp. 570-83 (1 pi.). 



I I 



