440 TEGUMENT ARY ORGANS 



Arnstein, according to which pieces of skin are put for twenty- 

 four hours into hme-water, the horny layer removed, the pieces 

 treated for five minutes with 0-25 per cent, gold chloride, reduced 

 in water, and the precipitate that forms on them removed by 

 putting into 0-25 per cent, cyanide of potassium and brushing. 



NowAK {Anal. Anz., xxxvi, 1910, p. 217) takes Unna's Orcein- 

 wasserblau mixture (Wasserblau O.D., 1 part, orcein 1, acetic 

 acid 5, glycerin 20, alcohol 50, water 100) and adds to it 1 part 

 more of orcein. To 10 c.c. of this he adds at the moment of 

 using 10 c.c. of 1 per cent, solution of eosin in alcohol of 80 per 

 cent, and 3 c.c. of 1 per cent, solution of hydroquinone. Stain 

 for five to ten minutes, rinse, stain for ten minutes in 1 per 

 cent, aqueous solution of safranin, wash, treat for thirty minutes 

 with 0-5 per cent, solution of bichromate of potash, dehydrate 

 and mount. 



Similarly Dogiel, Folia Neurobiol., iv, 1910, p. 218 (also 

 employing Bielschowsky's neurofibril method). 



937. Corpuscles of Meissner and of Krause (Cornea and Con- 

 junctiva). Dogiel {Arch. f. mik. Anat., xxxvii, 1891, p. 602, 

 and xliv, 1894, p. 15) employs the methylen blue method ; for 

 details see previous editions. 



See also Longworth's methods, Arch. mik. Anat., 1875, p. 655. 



938. Similar Objects. Papillae Foliatae of the Rabbit, Hermann, see 



Zeit. iviss Mik., v, 1888, p. 524 ; Arnstein, ibid., xiii, 1897, p. 240. 

 Olfactive Organs of Vertebrates, Dogiel, Arch. mik. Anat., 1887, p. 74. 

 Organs of a " Sixth Sense " in Amphibia, Mitrophanow, Zeit. wiss. 

 Mik., v, 1888, p. 513 (details as to staining with " Wasserblau," for 

 which see also Biol. Centralb., vii, 1887, p. 175). Nerve-endings in 

 Tongue of Frog, Fajerstain, Arch, de Zool. exper. et lien., vii, 1889, 

 p. 705. Tongue of Rabbit, von Lenhossek, Zeit. iviss. Mik., xi, 1894, 

 p. 377 (Ramon y Cajal's double Golgi method), 



939. Cornea. There are three chief methods — the methylen 

 blue, the silver, and the gold method. 



For the ineihylen blue method see particularly § 377. 



Negative images of the corneal cells are easily obtained by the 

 dry silver method (Klein). The conjunctival epithelium should 

 be removed by brushing from a living cornea, and the corneal 

 surface well rubbed with a piece of lunar caustic. After half 

 an hour the cornea may be detached and examined in distilled 

 water. 



In order to obtain positive images of the fixed cells the simplest 

 plan (Ranvier) is to macerate a cornea that has been prepared 

 as above for two or three days in distilled water. There takes 

 place a secondary impregnation. 



The same result may be obtained by cauterising the cornea of 

 a living animal as above, but allowing it to remain on the living 

 animal for two or three days before dissecting it out, or by treating 



