174 THE AMERICAN MONTHLY [June, 



ing the capillaries can be clearly distinguished by their 

 blue staining we can expect the nerve-endings to be 

 stained also, the former, however, will at once strike the 

 eye, and so this process will require but little time and 

 labor. In case the staining fluid does not acquire a blue- 

 ish tint it had best be poured off and be replaced by a 

 second quantity. 



The muscle-bundles, when sufficiently stained, are 

 washed thoroughly in tap or well water and then thrown 

 into glycerine, which is best changed a few times ; and 

 in this fluid they are now kept until they are to be further 

 examined. Then one or several of the little bundles are 

 taken from the glycerine and teased out, or, rather, split 

 up further, in such a way that the fibres are disarranged 

 as little as possible, and treated with acetic acid. If one 

 is in a hurry, the teased out bundles are placed in a 

 watch-glass of acetic acid, which is allowed to act until 

 the dark blue stain of the tissue is converted into a violet 

 one. If there is no lack of time, the muscle-bundles are 

 kept in a mixture of acetic acid and glycerine until they 

 have assumed a lighter color. A little experience will 

 soon show the details«of this part of the process. 



The muscle, when taken out of the staining fluid, has 

 a uniformly blue appearance; the nuclei only have a 

 black-blue color. The acetic acid now has this efl"ect, 

 that the substance of which the bulk of the muscle sub- 

 stance is built up, readily parts with its color, while the 

 fibre system of Gerlach (according to others, the sarco- 

 plasma), which by its regular thickenings and cross fibrils 

 produces the cross-striation, retains the stain to the same 

 degree that nerve-fibres do. 



In a successful specimen, therefore, the muscle- fibres 

 as a whole appear pale blue, while their narrow cross- 

 striations (and longitudinal fibrils) have a deeper blue 

 color. The pale nerve-fibres have a similar hue, while 



