556 SUSIMARY OF CURRENT RESEARCHES RELATING TO 



Secreting Cells of Intestinal Epithelium.* — Herr J. Pancth has 

 made a detuiled iuvcstigation of the histology of the secreting cells of 

 epithelium of the small iutestine. The subjects of research were mainly 

 newt aud mouse. By far the fittest staining reagent was safranin, used 

 after Pfitzner's method. 



His chief conclusions are as follows: — 



The goblet cells of the small iutestine arise from ordinary epithelial 

 cells. The secretion appears first in the form of granules. A portion 

 of the protoplasm aud the nucleus persist but undergo certain changes. 

 If a reticulum be found in the theca of these goblet-cells, it is not proto- 

 plasmic, but consists of secretion. After the secretion is emptied, the 

 goblet-cell becomes again epitlielial. 



In the crypts of various mammalian intestines, secreting cells occur 

 which are neither goblet-cells, nor mucous, nor pancreatic. They lie at 

 the bottom of the crypts, and are filled with granules of variable, and 

 often large, size. 



Spinal Ganglion-cells-t — Herr H. Daae has investigated the spiual 

 ganglion-cells of mammals, and especially those of the horse. His chief 

 results are as follows : — The spiual ganglion-cells of the horse are so far 

 unipolar, since each cell is associated with one large nerve-fibre. But 

 only in some cases is this process undivided. Often it divides within or 

 outside the capsule into many thin medullary fibres, which may 

 ramify and form by the union of their smaller branches a coil. From 

 this there issue, in variable number, terminal fibres, without medullary 

 sheath, and in connection with the body of the cell. These the author 

 calls " origin fibres." Where only two such origin fibres are present 

 the cells arc therefore bipolar, aud the poles lie apart. A\'here there are 

 more than two origin fibres, the cells are multipolar, even though the 

 multiple processes unite into one main fibre. The peculiar ramification 

 aud reunion of the fibres in the aforesaid coil appears to have been 

 hitherto overlooked. 



Axis-cylinder and Nerve-cells. J— Dr. J. Jakimovitch has investi- 

 gated, by tlie silver nitrate method, the histology of the nervous system. 

 His objects of investigation ranged from mammals to fishes, and also 

 included insects. A short summary of the history of i)ast research is 

 prefixed. 



The chief conclusions arrived at are as follows : — The axis-cylinder 

 and the nerve-cell are constructed on the same tyj)e. The latter is only 

 a nucleated enlargement of the former. Both consist of delicate fibrils 

 and an intermediate substance. The primitive fibrils include two 

 distinct substances ; a clear unstained component alternates with a 

 brown-stained material, so as to produce a striated appearance. The 

 stained substance is dense, elastic, and more solid than the clear sub- 

 stance. The two may be separated by maceratiou, and the primitive 

 fibril is resolved into nervous particles (" particules nerveuses "), which 

 form the primitive elemcuts. They are irregularly disposed in the 

 cylinder and cell in the resting state ; but group themselves to form 

 striae during activity. The striae are nowise artificial ; their state varies 

 after death. The same essential appearances are seen throughout the series. 



* Areb. f. Mikr. Anat , sxxi. (18S8) pp. 113-91 (3 pis.)- 



t Ibid., pp. 223-35 (2 pis.). 



X Jouru. du I'Anat. et de la Physiol., xxiii. (1888) pp. 142-G8 (1 pi.). 



