CHAPTER XXVIT. 



TEGUMENT ARY ORGANS. 



714. Epithelium. Both for surface views and for sections good 

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

 blue method, the perchloride of iron and pyrogallol method of the 

 Hoggans, 375, the osmic acid and pyrogallol process, 374, and by 

 iron-hcematoxylin. 



For the purpose of separating the epidermis from the cerium, 

 LOEWY (Arch. mik. Anat., xxxvii, 1891, p. 159) recommends mace- 

 rating for twenty-four to forty-eight hours, at a temperature of 

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

 J per cent. (PHILTPPSON) is also good. MINOT (Amer. Nat., xx, 

 1886, p. 575) macerates embryos for several days in 0-6 per cent, 

 salt solution, MTTROPHANOW (Zeit. iviss. 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. 



MAYER (Lotos, 2, xii, 1892) exposes the cornea or membrana 

 nictitans 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." 



715. 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., Hi, 1898, p. 1. KOLOSSOW used an osmic-acid- 

 tannin stain, 374. 



See also FLEMMING, Anat. 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. 



716. 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 



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