1895.] MICROSCOPICAL JOUKjVAL. 1*76 



the medullated nerve-fibres are darker. Tlie nuclei are 

 stained black-blue. A difference between the nuclei of 

 different tissues is not apparent. 



The most beautiful specimens I have procured from 

 muscle-bundles were those which, after being- stained, 

 had been kept in glycerine eight to ten months, to wliich 

 I believe, I had added borax. In this material I found 

 many sarcolemma sheaths empty and partly empty, 

 allowing thus the nerve terminations to appear very dis- 

 tinctly, and tlie nerves supplying the capillaries to show 

 with unusual clearness. Apparently, the borax had com- 

 pleted the i^rocess which the acetic acid had begun, viz., 

 solution of the cement substances. This material was 

 not treated with acetic acid, and perhaps by using thicker 

 muscle-bundles one might obtain material not overstained 

 where the washing out of the stain by the acetic acid 

 would not be necessary. 



Tliese directions are suitable for ordinary muscles of 

 the frog. The heart requires a milder process, nor is it 

 necessary that the bladder remain for eighteen hours in 

 fluid a. The intercostal muscle of the rat, however, 

 required more than twenty-four hours, so that different 

 tissues require different modifications of the method. 



If a number of muscles are to be investigated, the 

 vascular system of the frog is first washed out with a 

 and then as much of it forced into the vessels as can be 

 gotten into them. After this procedure it is an easy task 

 to split up the cut-out muscles which one may select, in- 

 to smaller pieces, with the aid of needles and the handles 

 of a scalpel. 



To facilitate the obtaining of pieces small enough for 

 the staining fluid and to make the mechanical separation 

 of the muscle fibres very thorough, I take the pieces of 

 muscle soaked in glycerine — before they are stained — 

 place them between two panes of glass and subject them 



