CHAPTER XXXII. 435 



again within twenty-four hours. Wash out for at^ least six hours in 

 pure acetone, changed two or three times. Make paraffin sections 

 and bring them through xylol and acetone into distilled water ; 

 silver for three days at about 37 C. in 20 per cent, solution of 

 silver nitrate. Put for ten minutes into a mixture (at least three 

 days old) of 1000 parts of water, 10 of sodium acetate, 5 of gallic 

 acid, and 3 of tannin (to be changed if it becomes turbid). Mount 

 at once or tone until grey (five minutes) in 80 parts of water with 17 

 of 2 per cent, ammonium sulphocyanide and 3 of 2 per cent, gold 

 chloride ; fix for a few seconds in 5 per cent, sodium hyposulphite. 

 Neurofibrils grey-violet, shown in cells, dendrites, and axons. 

 Terminal buds of Held also clearly shown, and nothing else 

 stained. One may counterstain in any way, even by Weigert's 

 or Benda's methods for neuroglia stain. 



The methylene blue intra vitam method is important, and may be 

 usefully employed for the study of neurofibrils. See the processes 

 of Apathy, Dogiel, and Bethe in Chapter XVI. 



C. Methods for the Demonstration of Golgi's Internal Apparatus. 



844. Introduction. The discovery of the " apparato reticolare 

 interno " was made by Golgi in 1898 by means of his rapid process 

 (see Chapter XXXIV). Soon afterwards he had recourse to a 

 mixture due to Veratti (see next paragraph), and Negri, Pensa, and 

 others of Golgi' s pupils found that the internal apparatus is not a 

 peculiarity of nerve cells. In 1902 Kopsch showed that the 

 apparatus can be stained by a simple immersion of nervous tissues 

 (spinal ganglia) into 2 per cent, osmic acid for eight to ten days. 

 Since then the apparatus was shown to exist in almost every kind 

 of cells, and new processes proposed for its demonstration in nervous 

 and other tissues by Sjovall, Golgi, Ramon y Cajal, Gatenby, Da 

 Fano. 



As the methods of Kopsch and Sjovall, the Mann-Kopsch method, 

 and Gatenby's Mann-Kopsch-Altmann combination have already 

 been fully discussed in Chapter XXVI, and particularly described 

 in 692 694 and 696, there remain to be described here only those 

 methods which are particularly suitable for the study of the internal 

 apparatus in nervous tissues, with exception of Golgi's rapid process, 

 for which see Chapter XXXIV, 882. 



845. GOLGI- VERATTI'S Method (see GOLGI, Anat. Anz. Verh. Anat, 

 Ges., xiv, 1900, p. 174). Small pieces are hardened for a time 



282 



