372 CHAPTER XXIX. 



the most suitable) removed and exposed to the air for three 

 or four hours in a moist chamber, and finally examined in 

 salt solution. 



G-ERLACH (Sitzb. k. math.-phys. CL k. bayer. Akad. Wiss. 

 Munchen, 1889, ii, p. 125 ; Zeit. f. wiss. Mik., vii, 2, 1890, 

 p. 220) injected frogs, either through the abdominal vein or 

 through the aorta, with 4 to 5 c.c. of a 1 : 400 solution in 1 

 per cent, salt solution, and examined pieces of muscle (pre- 

 ferably the head and eye muscles) in serum of the animal, 

 afterwards fixing the preparations with picrate of ammonia 

 and mounting in glycerin jelly. 



The procedure of DOGIEL has been given in 326. 



667. Nerve-endings the Gold Method. FISCHER (Arch. f. 

 mik. Anat., 1876 ; p. 365) used the gold method of LOWIT, 

 351. 



BTEDERMANN in the paper quoted in the last section re- 

 commends for Axtacus a similar procedure, the preliminary 

 treatment with formic acid being omitted, and the muscles 

 being put for a couple of days into glycerin after reduction 

 in the acid. 



RANVIER (Traite, p. 813) finds that, for the study of the 

 motor terminations of Vertebrates the best method is his 

 lemon-juice and gold-chloride process ( 353). The delicate 

 elements of the arborescence of Kiihne are better preserved 

 by this method than by the simple method of Lowit. 



668. Nerve-endings the Silver Method. RANVIEU employs 

 it as follows (ibid., p. 810) : Portions of muscle (gastrocnemius 

 of frog) having been very carefully teased out in fresh serum, 

 are treated for ten to twenty seconds with nitrate of silver 

 solution of 2 to 3 per 1000, and exposed to bright light 

 (direct sunlight is best) in distilled water. As soon as they 

 have become black or brown they are brought into 1 per cent, 

 acetic acid, where they remain until they have swelled up to 

 their normal dimensions. 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. 



