400 CHAPTER XXXLI. 



of 1 per cent, gold chloride (until blackish-grey). He fixes 

 for 3 to 5 minutes in 10 c.c. of sodium hyposulphite 

 of 5 per cent, with one drop of acid sodium sulphite, and 

 washes out for 24 hours in distilled water. 



PATON (Mitth. Zool. Stat. Neapel, xviii, 1907, p. 576) fixes 

 fish embryos in 4 per cent, formol neutralised with carbonate 

 of magnesia, makes both silver baths only f to 1 per cent, 

 strong, washes with weak acetic acid, and reduces in 10 c.c. 

 of 1 per cent, hydroquinon with 1 c.c. of formol. After 

 toning, he stains with 1 per cent, solution of eosin in 

 absolute alcohol. 



SAND (G. R. Ass. Anat. Bruxelles, 1910; Billiugr. anat. 

 Supp.j 1910, p. 128) gives the following as entirely certain 

 for man, dog, cat and rabbit. Specimens of not more than 

 5 mm. in thickness are fixed for 48 hours in a freshly 

 prepared mixture of 90 parts of acetone and 10 of 

 nitric acid (change for fresh after half an hour and once 

 again within 24 hours). Wash out for at least 6 hours in 

 pure aceton, changed two or three times. Make paraffin 

 sections, and 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 acetate of sodium, 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, solution of sulphocyanide of ammonium and 

 3 of 2 per cent, solution of gold chloride, and fix for a few 

 seconds in 5 per cent, solution of hyposulphite of soda. 

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

 Terminal buds of Held also clearly shown, and nothing else 

 stained. You may after-stain in any way, even with Weigert's 

 or Benda's neuroglia stain. 



BOEKE (Anat. Anz., xxxv, 1909, p. 136) says that Bielschowsky's 

 method will succeed after many kinds of fixation, even that by picrc- 

 sulphuric acid. For embryos he finds the best is 10 parts of formol to 

 90 of 60 per cent, alcohol, the objects being washed out with pure 

 formol of 10 to 12 per cent, until all the alcohol is removed, before 

 silvering. 



LUGARO (Monit. Zool. ItaL, xv, 1S04, p. 353) has a highly complicated 

 method with collaryol (colloidal silver) which has not met with favour. 



