300 MUSCLE AND TENDON. 



by the acid serving to make up for the shrinkage caused by 

 the nitrate of silver) . They are then examined in a mixture 

 of equal parts of glycerin and water. 



This process gives negative images, the muscular substance 

 is stained brown, except in the parts where it is protected by 

 the nervous arborescence, which itself remains unstained. 

 The gold-process gives positive images, the nervous structures 

 being stained dark violet. 



633. Motor Plates, Other Methods. 



BBEMER (Arch.f. mik. Anat., 1882, p. 195). Impregnate according to the 

 method of Fischer, ante, 631, and soak for two or three weeks in glycerin 

 containing 20 per cent, of formic acid. Mount in glycerin containing 1 per 

 cent, of formic acid. 



CIACCIO (Journ. de Micrographie, 1883, p. 38). Lemon-juice followed by 

 1 per cent, solution of double chloride of gold and cadmium, and reduction 

 partly in the light and partly in concentrated formic acid in the dark. 



WOLFF (Arch.f. mile. Anat., 1881, p. 355). Study of the living muscle in 

 salt solution. 



GAEL SACHS, ibid. Dilute acetic acid followed by very weak picric acid 

 for twenty-four hours. After mounting in glycerin, this gives very trans- 

 parent preparations. 



KEAUSE (Intern. Monatschr.f. Anat. u. Hist.; Zeit.f. wiss. Mik., 1885, 

 p. 547). A muscle is put for three or four hours into concentrated solution 

 of oxalic acid, then boiled for two minutes in water, treated for twenty-four 

 houro with O'l per cent, osmic acid, and mounted in glycerin. 



NEGEO (Zeit. f. wiss. Mik., v, 2, 1888, p. 240). Make the following 

 solution : 



Concentrated solution of ammonia alum . . 180 parts 

 Griibler's saturated alcoholic solution 



of haematoxylin ...... 2 



Mix, and let the mixture stand for a week exposed to the air, and add 

 25 c.c. each of methyl alcohol and glycerin. A drop of this is brought on to a 

 fresh preparation of muscle of Tropidonotus natrix, Lacerta viridis, or 

 Rana, and in a few minutes the stain is washed out and the preparation 

 mounted in balsam. 



BOCCAEDI (see Zeit. f. wiss. Mik., iv, 4, 1887, p. 492). Preparations 

 treated according to Kanvier's lemon-juice method or his formic-acid method, 

 are washed in distilled water and put for a couple of hours into oxalic acid 

 of from O'l to 0'25 or 0'30 per cent., or, better, into a mixture of 



Pure formic acid 5 cc. 



1 per cent, oxalic acid . . . . . 1 



Distilled water 25 



Then washed and mounted in glycerin. 



KUHNE (Zeit. f. Biol, xxiii, v, 1887, p. 1 ; Zeit.f. wiss. Mik., iv, 4, 1887, 

 p. 495). This paper contains a critical review of the different gold-methods, 

 of which the following are the principal conclusions : 



