174 SERIAL SECTION MOUNTING. 



already stained objects, because it is found to work more 

 pleasantly than any other method. I recommend xylol or 

 naphtha for clearing, in preference to turpentine. 



Good collodion is essential in this process. 



STRASSER (Zeit. f. wiss. Mik., iv, 1, 1887, p. 45) recommends 

 a mixture of 2 parts collodion, 2 parts ether, and 3 parts 

 castor oil ; or (Ibid., vi, 2, 1889, p. 153) 2 parts of collodion 

 with one of castor oil, the sections being painted over with a 

 thicker solution, viz. collodium concentratum duplex, 2 to 3 

 parts, castor oil, 2 parts, and the slide being plunged at once, 

 without warming, into a bath of turpentine, in which it 

 remains till the paraffin is dissolved (2 to 10 hours, somewhat 

 less if the whole be put in a stove). The turpentine suffices 

 to harden the collodion (benzin, benzol, and chloroform have 

 the same effect). 



GAGE prefers preparing slides with a layer of pure collodion, 

 which is allowed to dry, and is rendered adhesive at the instant 

 of using by brushing with clove oil. 



SUMMERS (Amer. Hon. Hie. Journ., 1887, p. 73 ; Zeit. f. wiss. 

 Mik., iv, 4, 1887, p. 482) also employs a dry layer of collodion, 

 which he renders adhesive after the sections are arranged on 

 it, by wetting with a mixture o equal parts of alcohol and 

 ether. As soon as the mixture has evaporated, the sections 

 are found to be fixed. 



316. Strasser's Collodion-Paper Method (Zeit.f. wiss. Mik., iii, 3, 

 1886, p. 346). This is an extremely complicated modification of Weigert's 

 collodion method for celloidin sections (post, 327). 



In a later communication (Ibid., vi, 2, 1889, p. 154) STBASSEE describes 

 the following modified form of the process. For sections of already stained 

 objects paper is prepared by saturating it evenly and thinly with wax, its 

 surface is prepared with the thin collodion mixture given in the last para- 

 graph, the sections are arranged and painted over with the thick mixture as 

 there described, and the whole is brought into turpentine, which dissolves 

 the wax and sets free the plate of collodion containing the sections. The 

 plate is then either mounted on glass in the usual way, or is treated as 

 follows. The paper is lifted out of the turpentine, with the collodion plate 

 lying free on it ; the collodion plate is painted over with a thickish layer of 

 thick solution of resin, and covered (as with a cover-glass) with tracing 

 paper. The whole is then allowed to dry a little on filter-paper, and put 

 away, lightly wrapped between folds of filter paper, so that the air may have 

 access to it, in an album (avoiding pressure). For the microscopic study of 

 such preparations they are mounted between glass with some clearing fluid. 

 such as oil or kreasote. If it be required to definitely mount them in tin- 



