CHAPTER XXYJJ. 

 TEGUMENTAUY ORGANS. 



654. Epithelium. Both for surface views and for sections 

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

 methylen Hue method, the percJiluride of iron and pyrogallol 

 method of the Hoggans, 375, the osmic acid and pyrogallol 

 process, 374, and by iron-hsematoxylin. 



For the purpose of separating the epidermis from the 

 corium, LOE\VY (Arch. mik. Anat., xxxvii, 1891, p. 159) 

 recommends macerating 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. (PHILIPPSON) is also good. 

 MINOT (Amer. 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 1 hour in one-third alcohol, and, if 

 need be, 24 in stronger alcohol. 



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

 nictitans of Rana, Bufo, and Hua 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." 



655. 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, 374. 



See also FLEMMING, Anat. Hefte, \ Abth, vi, 1895, p. 1. 



Besides maceration, impregnation may be useful ; MITRO- 

 PHANOW (Arch. Anat. Phys., Phys. Abth., 1884, p. 191) has 

 used gold chloride. 



