Literary Notices. xxxix 



for 12 hours in saturated copper acetate and treated with Weigert's hematoxylin 

 for six hours. They took up the stain only very faintly. 



Go M. Mordanting for i6 hours in 5 per cent, potassium bichromate and 

 treating for 12 hours with Weigert's hematoxylin gave the same results. 



61 M. Mordanted similar sections in saturated copper acetate for 12 hours, 

 washed and then treated for 16 hours with 5 per cent, potassium bichromate and 

 stained for 12 hours with Weigert's hematoxylin. They take up the stain to 

 some extent, but upon applying Weigert's decolorizer the white matter bleaches 

 before the grey. I reversed the order of the mordants, first the bichromate, 

 then the copper, with the same result. 



Osmic acid, iron alum and ammonium molybdate are the three mordants 

 which Bolton found to give the most satisfactory results with the human brain 

 after six months hardening in 5 per cent, formalin. To test their value with the 

 fishes the following experiments were tried : 



62 M. The brain, which had been hardened for five months in 10 percent, 

 formalin, was washed in water and sectioned in paraffin. The sections were 

 mordanted for 15 minutes in i per cent, osmic acid, stained for I5 hours in 

 Kultschitzky's acid hematoxylin and decolorized by the method of Weigert. 

 This gives a diffuse brown stain with the nerve fibers not at all differentiated. 



63 M. Other sections were given the same treatment save that they were 

 stained in Weigert's hematoxylin. The result is similar, the stain not being 

 quite so intense. 



64 M. Sections prepared like the last were mordanted for I4 hours in 2 per 

 cent, iron alum, stained in Weigert's hematoxylin and decolorized by the meth- 

 od of Weigert. This gives a stain similar to the last, though both cells and 

 fibers are slightly better differentiated. 



61; M. As before, but stained in Kultschitzky's hematoxylin, and with the 

 same unsatisfactory result. 



66 M. Similar sections were mordanted for I4 hours in 2 per cent, ammo- 

 nium molybdate and stained in Kultschitzky's hematoxylin. They took the 

 stain only faintly and the fibers decolorized wholly, leaving all nuclei vividly 

 stained. 



67 M. Like the last, but stained in Weigert's hematoxylin. They decolor- 

 ize wholly with no differentiation. 



The six cases last given resemble Bolton's best methods, save that 

 he differentiated by the method of Pal. Having found that in several 

 of these cases that method gave still worse results than the method used, 

 I conclude that none of these methods are adapted to fish tissues. Be- 

 ing very desirous of utilizing formalin hardening material, I next tried 

 several modifications of the method used by Edinger in his studies up- 

 on the reptile brain. 



68 M. The brain, which had been hardened for five months in 10 per cent, 

 formalin, was washed in water and then soaked for six days in Weigert's fluid, 



Water, lOO cc. 



Potassium bichromate, 5 g. 



Chrome alum, 2 g. 



