METHOD III. 



THE BETHE METHOD.' 



A special method for the differentiation of the neurofibrillae 

 and "Golgi net." As here given, the method is applicable to 

 vertebrate nervous tissue. 



SPECIAL REAGENTS REQUIRED. 



A. The fixing fluid {^i, per cent nitric acid). — 



Nitric acid (C. P. concentrated), 5 cc. 

 Distilled water, 100 cc. 



B. Hardening reagent. — 



g6 per cent, alcohol, 600 cc. 



C. Developing fluid (ammoniated alcohol). — 



Ammonia (C. P. concentrated, sp. G. 95), 8 cc. 



Distilled water, 24 cc. 



96 per cent, alcohol, 64 cc. 



D. Developing fluid (hydrochloric acid-alcohol). — 



Distilled water, 24 cc. 



Hydrochloric acid (C. P. concentrated), 8 cc. 



q6 per cent, alcohol, 80 cc. 



E. Molybdating fluid (4 per cent, ammonium mglybdate). — 



Ammonium molybdate, 4 g. 

 Distilled water, 100 cc. 



F. The stain (aqueous toluidin blue). — 



Toluidin blue, o.i g. 

 Distilled water, 300 cc. 



' A. Bethe, " Das Molybdanverfahren zur Darstellung der Neurofibrillen und 

 Golginetze im Centralnervensystem. " Zeitschrift fur wiss. Mikroskopie, Bd. XVII, 

 H. I, May, 1900. The procedure given varies very little from that published 

 by Bethe. The method is tedious, and in some of its steps seems to be unneces- 

 sarily so, but the few efforts made in this laboratory to shorten or simplify it have 

 proved unsatisfactory. For the possible chemical action of the various reagents the 

 student is referred to Bethe's discussion of the method. Alsc see the original paper 

 for the application of the method to invertebrates 



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