402 OHAPTBIt XXXIT. 



water is poured on to them, they are again stoved for ten 

 minutes, rinsed with water, treated with 96 per cent, alcohol 

 till no more colour comes away, and passed through absolute 

 alcohol and xylol into xylol balsam. 



The method is also applicable to invertebrates, for which 

 other fixations than nitric acid are admissible, and the 

 impregnation with the niolybdate may be done on the 

 sections instead of the uncut tissues. The results are not so 

 certain as for vertebrates. 



LuGARO (Bz'i;. Pat. New. Ment., Pirenze, x, 190.5, p. 260) modifies 

 this by fixing in nitric acid dissolved (to 1 per cent.) in aeetov. 



DoNAGGio [Ann. Nerrol. Napoli, 1904, p. 161) fixes pieces 

 not more than 5 mm. thick for five to six days in pijridin, 

 changed at least once, washes in water, and mordants for 

 twenty-four hours in ammonium molybdate 4 grms., water 100, 

 hydrochloric acid 4 drops. Wash, get into paraffin, treat 

 sections on slide for one minute with water, stain for three 

 to thirty minutes in a 1 : 10,000 solution of ihionin, and 

 mount ; or, better, first treat again for fifteen to thirty 

 minutes with molybdate solution. 



JiDEEHOLM (Arch. mih. Anat., Ixvii, 1905, p. 108) finds that the 

 pyi'idin causes enormous shrinkage, and that the thionin agglutinates the 

 fibrils. 



Paeayicini {Bull. Mus. Z. Anat. Comp., Torino, xx, 1905, p. 514) 

 fixes and mordants in the dark, and differentiates after staining with 

 extremely weak hydrochloric acid. 



See also Tomaselli, Zeit. wins. Mile, xxiii, 1907, p. 422, and 

 MONTANAEi, ibid., xxviii, 1911, p. 22, who describes observations which 

 seem to throw douljt on the objectivity of the network described by 

 Donaggio. 



773. Neurofibrils, Apathy's Hsematein Method {Mittli. Zool. Stat. 

 Neapel., xii, 1897, p. 712). — Material may be fixed with sublimate, liquid 

 of Zenker, picro-siilphuric acid, or any mixtui-e that is not inimical to 

 staining with alum hssmatoxylin, and should be preserved in 90 per 

 cent, alcohol. Portions are stained for at least forty-eight hours in the 

 hiEmatein solution 1 A, § 259, and are then washed for up to twenty-four 

 hours in absolutely pure distilled water, preferably suspended therein. 

 Before the stain has become washed out of the neurofibrils, it is fixed 

 therein by putting the preparations for three to five hours into spring 

 water, after which they are put back tor not more than two hours into 

 distilled water, dehydrated as rapidly as possible by hanging them up 



