NEUROKERATIN 519 



50 c.c. ; new-born kittens, 15 to 25 e.c. As soon as the animal 

 used is dead, the brain is removed, divided into two to four pieces, 

 and these pkmged in 10 per cent, ammonium molybdate to which 

 1 drop of HCl for every gram of ammonium molybdate is added. 

 Here they remain for about twenty-four hours at 0° C. Pieces are 

 then washed for two hours in running tap-water, passed quickly 

 through the ascending series of alcohols into absolute alcohol, 

 and, lastly, imbedded in paraffin in the usual way. 



1053. Ramon y Cajal's Diffusion Process {Rev. Trim. Micr., 

 i, 1896, p. 123). The brain is exposed, and by means of a sharp 

 razor the cortex is divided into slices about 2 mm. thick. The 

 slices are then covered on both sides, either with finely powdered 

 methylen blue or impregnated with a saturated solution of the 

 same and replaced in their natural situation. The brain is covered 

 over again with its case for about half an hour, after which the 

 slices are removed and fixed for a couple of hours in Bethe's 

 ammonium molybdate solution. They are then washed and 

 hardened for three or four hours in a mixture of 5 parts of chloro- 

 platinic acid, 40 parts of formalin, and 60 parts of distilled water. 

 After another quick wash and a brief treatment (? a few minutes) 

 with a 1 : 300 alcoholic solution of chloroplatinic acid, they are 

 dehydrated and imbedded in paraffin. The sections may also be 

 quickly treated with the same weak alcoholic solution of chloro- 

 platinic acid, cleared with xylol or bergamot oil, and mounted in 

 the usual way. 



Catois' Method for Fishes (C. R. Ac. Sc, cxxiv, 1897, p. 204). 

 Small quantities (2 to 3 c.c.) of a concentrated solution of 

 methylen blue, prepared with physiological salt solution, is 

 injected into the branchial vessels or intramuscularly. The 

 brain is removed after half an hour, divided into slices, and 

 then left for another half hour in the same concentrated solution 

 used for injecting the animal. The slices are then fixed in the 

 usual ammonium molybdate solution, or in Cajal's chloroplatinic 

 acid mixture. 



See also the valuable account of Dogiel, Meihylen-hlau zur 

 Nervenfdrbung in the Enzykl. mikr. Techn., 2nd ed., 1910, and the article 

 of Gordon in Anat. Bee, iv, 1910, p 267 ; and that of Michailow in 

 Ztschr. wiss. Mikr., xxvii, 1910, p. 1 , in which the literature of the 

 subject is critically discussed. 



1053 bis. Methods demonstrating Neurokeratin Network. Platner 



(Ztschr. zviss. Mikr., vi, 1889, p. 186) fixes for several days in a 

 mixture of 1 part of Liq. Ferri Perchlor. (Ph.G., ed. 2) and 3 

 to 4 parts of water or alcohol, washes out well in water and stains 

 for several days or weeks in a concentrated solution of " Echt- 

 griin " (dinitroresorcin) in 75 per cent, alcohol. See also Beer, 

 Jahrb. Psychiatric, ii, 1893. 



