RAMIFICATIONS OF NERVES IN MUSCLE. 301 



(1). The method of Lowit is particularly applicable to thin entire (un- 

 teased) muscles. 



(2). Preliminary treatment with weak (0'5 per cent.) formic acid, and re- 

 duction in dilute glycerin containing one fourth to one fifth volume of 

 formic acid, in the dark, is a good process for muscles of warm-blooded 

 animals. 



(3). The same process, with omission of the preliminary acidification, is to 

 be recommended for cold-blooded animals. 



(4). The method of GOLGI (Mem. delle R. Acad. di Sci. di Torino, ii, 

 xxxii) is applicable to all classes of objects. It is as follows : Acidification 

 with O'o per cent, arsenic acid, impregnation in 0'5 per cent, solution of 

 double chloride of gold and potassium, and reduction in 1 per cent, arsenic 

 acid in sunlight. 



(5). A modification of the last, consisting in impregnation in a mixture 

 containing 0'5 per cent, arsenic acid, 0'25 per cent, chloride of gold and 

 potassium, and O'l per cent, osmium, and reduction as before, is stated to be 

 particularly applicable to Reptilia. 



Kiihne also remarks that teasing ought to be done in the gold solution. 

 Specimens should be removed from the gold every few minutes, and from 

 the reducing medium every hour, so that the right duration both of impreg- 

 nation and reduction may be hit off. Preliminary acidification is unfavour- 

 able to the preservation of the arborescence, and the treatment with acids 

 after impregnation is best abbreviated as much as possible. Mounting in 

 formic-acid glycerin is not favourable for the preservation of detail. This 

 is best studied in arsenic acid. Entire muscles are best mounted in balsam. 



634. Ramifications of Nerves in Muscle (MAYS, Zeit.f. Biol, 1884, 

 p. 449 ; Zeit.f. wiss. Mile., 1885, p. 242). Thin muscles are put into a freshly- 

 prepared mixture of 



0*5 per cent, solution of double chloride of gold and 



potassium ........ 1 gramme. 



2 per cent, solution of osmic acid . . . .1 



Water 20 



As soon as the nervous ramifications begin to make their appearance, the 

 muscles are brought into a mixture of 



Glycerin 40 grammes. 



Water 20 



25 per cent, hydrochloric acid ....! 

 in which they are left for about a day. 



Another method (for thick muscles) is as follows : The fresh muscle is 

 put for twelve hours into 2 per cent, acetic acid, and then into a freshly pre- 

 pared mixture of 



0'5 per cent, solution of double chloride of gold and 



potassium 1 gramme. 



2 per cent, osmic acid solution ....! 



2 per cent, acetic acid 50 ,, 



The muscle remains in this for two or three hours, until the nerves aro 

 impregnated, and then is put for a few hours into the glycerin and hydro- 

 chloric acid mixture. 



