MOTOR PLATES. 299 



iii, 1875, p. 1), and employed by himself in his researches on 

 the tactile corpuscles (Arch. f. mik. Anat., xii, p. 366). 



For birds, a muscle (viz. the M. complexus) is cut up into 

 strips 1 to 2 mm. thick and 10 mm. long, which are treated 

 with dilute formic acid (1 part of the acid of sp. gr. of 1*06 

 to 2 parts water) until they become transparent. (Daring 

 this maceration the strips are teased to facilitate the pene- 

 tration of the gold). They are then passed direct into 1 per 

 cent, gold chloride, and remain there a quarter of an hour. 

 They are then washed with water and placed, according to 

 Lowit' s method, in a solution of formic acid 1 part, water 

 3 parts, where they remain twenty-four hours. They are not 

 treated with the concentrated acid. 



For reptilia and for pisces the same method was adopted. 

 For amphibia the same method also, except that dilute acetic 

 acid was used in the first instance in the place of formic acid 

 to produce the necessary swelling of the tissues. 



632. Motor Plates (RANVIEK, Traite, p. 813). Ranvier finds 

 that for the study of the motor terminations of batrachia the 

 best method is his lemon-juice and gold-chloride process 

 ( 209). The delicate elements of the arborescence of Kiihne 

 are better preserved by this method than by the simple 

 method of Lowit. 



For the study of the motor plates of reptiles, fishes, birds, 

 mid mammals, he finds (ibid, p. 826) that his formic-acid and 

 gold-chloride method, 208, gives preparations infinitely 

 superior to those obtainable by the method of Lowit, but the 

 lemon- juice method is still better, especially for lizards and 

 mammals. The branches of the terminal arborescence are 

 more regular than in preparations obtained by the formic- 

 acid process. 



He finds that the silver-nitrate method of Cohnheim is also 

 useful. He 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 (the swelling induced 



