—136— 



These methods give the best results when embr\'onic 

 tissues, or tissues taken from newly born or young animals, 

 are employed. 



Often when the methods above noted do not give good 

 results at the first trial, they may with success be repeated 

 on tlie same tissue. If after the tissues have been 2 or 3 

 days in the silver nitrate, the trial sections (free-hand 

 sections cut from the blocks, mounted and examined in 

 95% alcohol) sh.ow no staining, they may agiiin be 

 placed in the bichromate of potassium solution for several 

 days, and then again into silver. Good results follow a 

 second and even the third trial. 



Sections are cut into 95 % alcohol ; they may be made 

 either free-hand or, after surrounding with |)araflin or 

 embedding in celloidin, cut with the microtome. From the 

 alcohol, sections are placed for 15 minutes into creosote 

 then washed from 3 to 5 minutes in oil of turpentine, 

 out of which they are taken and arranged on the slide. 

 The excess of oil of turpentine is removed with filter paper, 

 and the sections are covered with balsam. The slideis now 

 carefully heated over an alcohol flame, until the balsam be- 

 comes so thick that on cooling, it at once hardens (3 to 5 

 minutes of careful heating are required, allow no bubl)les 

 to form) ; while the balsam is yet warm cover with a cover 

 glass which has been passed through the flame several 

 times; after cooling, the preparation is ready for study. 

 Mounted in this way, Golgi preparations do not fade* 



Gold Chloride (Ranvier's Lemon Juice Method). 



This method is especially useful for staining the nerve- 

 ending involuntary muscle. 



Place small pieces of a short muscle (intercostal of a 

 snake or guinea pig) in filtered lemon juice for 10 to 15 

 minutes (or until the tissue becomes transparent), wash 

 hastily in distilled water and transfer the tissue to a 1% 

 solution of chloride of gold, in which they remain for 15 to 

 20 minutes. The tissue is then again hastily washed in 



* Huber. Auatomischer Anzeiger. VII Jahrgang (1892), 

 No. 18. 



