CHAPTER XXXVI 

 TEGUMENTARY ORGANS OF METAZOA 



928. Epithelium. Both for surface views and for sections 

 good results are obtained by the nitrate of silver method, the 

 meihylen blue method, the perchloride of iron and pyrogallol method 

 of the Hoggans, § 414, the os7nic acid and pyrogallol process, 

 § 413, and by iron htsmatoxylin. 



For the purpose of separating the epidermis from the corium, 

 LoEWY {Arch. mik. Anat., xxxvii, 1891, p. 159) recommends 

 macerating for twenty-four to forty-eight hours, at a tempera- 

 ture of about 40° C, in 6 per cent, pyroligneous acid. Acetic 

 acid of i per cent, (Philippson) is also good. Minot {Anier. 

 Nat., XX, 1886, p. 575) macerates embryos for several days in 

 0-6 per cent, salt solution, Mitrophanow {Zeit. wiss. Mik., v, 

 1888, p. 573) for a quarter of an hour in 3 per cent, nitric acid, 

 then one hour in one-third alcohol, and, if need be, twenty-four in 

 stronger alcohol. 



IVIayer {Lotos, 2, xii, 1892) exposes the cornea or membrana 

 nicitans of Rana, Bufo, and Mus for half a minute to the vapour 

 of acetic acid, and then puts it into 0-5 per cent, salt solution. 



For ciliated epithelium see the methods of Engelmann under 

 " Mollusca." 



929. Intercellular Bridges (and Canals), Prickle Cells. See Ide, 

 in La Cellule, iv, 1888, p. 409, and v, 1889, p. 321 ; also KoLOSSOW, 

 Arch. mik. Anat., lii, 1898, p. 1. Kolossow used an osmic-acid- 

 tannin stain, § 413. 



See also Flemming, Aiiat. Hefte, 1 Abth, vi, 1895, p. 1. 



Besides maceration, impregnation may be useful ; Mitrophanow 

 {Arch. Anat. Phys., Phys. Abth., 1884, p. 191) has used gold 

 chloride. 



Unna {Monatsschr. prakt. Derm., xxxvii, 1903, p. 1) has 

 described a highly complicated process with Wasserblau and 

 orcein, see Zeit. wiss. Mik., xxi, 1904, p. 68. 



930. Plasma-fibrils of Epithelium. Kromayer's process {Arch, 

 mik. Anat., xxxix, 1892, p. 141) is as follows : Sections are stained 

 for five minutes in a mixture of equal volumes of anilin water 

 (§ 694) and concentrated aqueous solution of methyl violet 6 B. 

 They are well washed in water and treated with solution of 

 iodine in iodide of potassium until they become blue-black (one 

 to thirty seconds). They are again washed with water, dried 



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