10 PROFESSOR RUTHERFORD. 



Describe hoAV to harden, cut, and preserve nerve tissue. 

 1st. Cut perfectly fresh nerve tissue into pieces, not larger 

 than a walnut if possible, and (2nd) place them for twenty-four 

 hours in methylated spirit. 3rd. Place them for a week in 

 the following fluid : 1 part chromic acid, 2 parts potassium 

 bichrom., 1200 parts water. 4th. Place them in a fluid 

 twice this strength for four or six weeks. 5th. Make sections, 

 wet the knife with water or methylated spirit (if the latter, 

 the spirit must be afterwards thoroughly washed from the 

 sections Avith water). 6th. Place the sections for at least half 

 an hour in 1 part potass, bichrom., 200 parts water. 7th. 

 Wash in water frequently changed. 8th. Colour with car- 

 mine, 10 parts carmine, 500 parts of strongest ammonia, 100 

 parts glycerine. Gradually mix the ammonia with the 

 carmine in a mortar, and then add the glycerine. Lay the 

 sections in this fluid for a period varying from one to 48 

 hours. 8th. Place them at once in methylated spirit, or wash 

 them with distilled water to remove superfluous pigment. 

 Then place them in methylated spirit for at least twenty-four 

 hours ; they will then be ready for mounting. 9th. Place a 

 section on a slide, Avash it with absolute alcohol, or better, 

 put it in a watch glass containing absolute alcohol for a few 

 minutes, and then lay it on the slide. Wait until it dries some- 

 what (until it becomes sodden), then, 10th. Clarify it with 

 turpentine or clove oil. Insinuate a drop of either oil under 

 the section by means of a salle hair pencil. When it has 

 driven all the spirit into the air put a drop on the upper 

 surface. 11th. When sufiiciently clear put on a drop of 

 Dammar or Canada balsam solution, and then put on the 

 covering glass. 



D. 6. Uncoloured T. S. hardened spinal cord of cat. 



D 7. Carminised section of the saine. 



D 8. Carminised V. S. of the same. 



D 9. V. S. cerebellum of cat carminised. 



D 10. V. S, Cerebrum of cat carminised. Render this 

 one very transparent with clove oil. 



D 11. V. S. cerebrum of cat carminised. Render this 

 only semi-transparent. 

 The sections D 6 to D 11 are rendered transparent with 

 oil of cloves or oil of turpentine, and are mounted in Dammar 

 or Canada balsam. 



40. hung. Fresh kmg of cat. 



D 1. Thin section with scissors. Add salt solution. 

 Press in order to expel air. Add acetic acid. 



D 2. Section of hardened lung kept in methylated 

 spirit. Mount in glycerine. 



