304 MUSCLE AND TENDON. 



mixture of two parts one-third alcohol and part one 0*5 per 

 cent, acetic acid. The iris can then be isolated, and split 

 from the edge into an anterior and posterior plate, and these 

 stained according to the usual methods. 



641. Iris (KOGANEI, Arch. f. mik. Anat., 1885, p. 1). The 

 pigmented epithelium can be removed by brushing with a 

 small brush after prolonged maceration in solution of Miiller. 

 The pigment may also be bleached by chlorine water, which 

 however should only be allowed to act for a few hours, until 

 the pigment has become of a light brown ; complete de- 

 colouration may be obtained by prolonging the reaction for 

 twenty-four hours, but then the tissues suffer. (See Journ. 

 Roy. Hie. Soc., 1886, p. 874). 



See also, CANFIELD, in Arch. f. mik. Anat., 1886, p. 121 ; 

 and DOSTOIEWSKY, ibid., p. 91 (sections stained with macerated 

 oxylin and eosin, or (LiST, Zeit. f. wiss. Mik., iii, 4, 1886, p. 

 514) with Renaut's haematoxylic glycerin. 



642. Stomach of Triton (see STILLING and PFITZNER, in Arch, 

 mik. Anat., 1886, p. 396). 



643. Test for Smooth Muscle (RETTERER, Comptes Rend. Soc. 

 Biol., iv, 1887, p. 645; Journ. Roy. Mic. Soc., 1888, p. 843). 

 If a specimen of tissue be fixed in a mixture of ten volumes 

 of 90 per cent, alcohol and one volume of formic acid, well 

 washed, and stained for twenty-four to thirty-six hours with 

 alum carmine, the cytoplasm of smooth muscle will be found 

 to be stained red, whilst connective-tissue cells remain un- 

 stained, and are swollen. 



