CHAPTER XXVIII. 345 



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 

 process ( 366). 



See also the methods of APATHY, 368, 371. 



730. Nerve-endings the Silver Method. RANVIER employs it as 

 follows (ibid., p. 810) ; Portions of muscle (gastro-cnemius of frog) 

 having been very carefully teased out in fresh serum, are treated 

 for ten or 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 being 

 stained brown, and the nervous arborescence unstained. The gold 

 process gives positive images, the nervous structures being stained 

 dark violet. 



731. Nerve-endings the Bichromate of Silver Method. The 



rapid method of G-OLGI has been used by RAMON Y CAJAL for the 

 terminations of nerves and tracheae in the muscles of insects. See 

 Zeit. wiss. Mik., vii, 1890, p. 332, OT fourth edition. A modification 

 is used by WUNDERER, Arch. mik. Anat., Ixxi, 1908, p. 523. 



732. Muscle-spindles. See CILIMBARIS, Arch. mik. Anat., Ixxv, 

 1910, p. 692. Principally intra vitam methylen blue, by injection 

 through the internal carotid. For elastic fibres, Weigert's resorcin- 

 fuchsin, followed by 1 per cent, orcein acidified with HC1. 



Electric Organs. 



733. Electric Organs. RANVIER (Traite, Chap, xviii), finds that 

 osmic acid is the only reagent that will fix properly the terminal 

 arborisations on the lamellae. He injects a little 2 per cent, solution 

 under the surface of the organ, removes a small portion of it after 

 a few minutes, and puts it into a quantity of the same solution for 

 twenty-four hours. The electric plates may then be teased out 

 and examined in water, and will show the stag's horn ramifications ; 

 and the dissepiments between the columns will show the bouquets 



