Appendix. 149 



surrounding tissue if the specimen is allowed to stand for 

 two or three days in 10% nitric acid. The acid, however, 

 injures the other tissues. 



Muscles are generally more easily studied in alcoholic 

 specimens. Small blood-vessels should be injected either 

 with a pipette or with a hypodermic syringe. The use of 

 strong acetic acid will frequently aid in separating organs 

 that are firmly held together with connective tissue. 



Xylol may at times be advantageously used with small 

 objects that have been preserved in strong alcohol. The 

 xylol frequently clears the object in a most instructive way, 

 presenting in the process one organ-system after another. 1 



Glycerine may be advantageously used as a teasing 

 medium with many objects. Fragments of tissue thus iso- 

 lated may be kept under the cover-glass for a considerable 

 time. 



Schneider's aceto-carmine is a penetrating stain that can 

 be used with fresh tissues, either during the process of teas- 

 ing or after the objects are under the cover-glass. Material 

 thus stained may be washed in water and kept for a short 

 time by being mounted in glycerine. 



1 See page 83. 



