THE SKIN. 185 



CHAPTER X. 



THE SKIN, HAIRS, AND NAILS. 



Preparations 1-6. Sections of the skin. 



Portions should be selected for examination from 

 different parts of the body ; the palms of the fingers 

 or toes, the scalp, and a piece from some part of the 

 general surface ; e. g. the extensor surface of the fore- 

 arm. The skin of the scrotum may also be prepared, 

 to show the bundles of plain muscular tissue in the 

 subcutaneous tissue or dartos, and a small piece of 

 the ala of the nose, for the sake of the well-marked 

 sebaceous glands, which open into the follicles of the 

 minute hairs found in this situation. 



The following method of hardening the tissue can 

 be recommended : A small piece only is removed, 

 being obtained with as little of the subcutaneous 

 tissue as possible adhering to it. At the same time, 

 if it is desired to examine the larger sweat-glands, 

 this tissue must not be removed too freely, since 

 those bodies extend down into it. It will be found 

 that the fresh skin has a tendency to curl in at the 

 edges ; this should be prevented by pinning the piece 

 out on a piece of cork. The latter is then inverted 

 into a beaker containing a mixture of spirit and 

 chromic acid (equal parts of spirit and of half per 

 cent, solution of chromic acid). Here, while the 

 chromic acid hardens the tissue pretty uniformly, 

 the spirit tends to prevent the epidermis from break- 

 ing away, as it is apt to do when placed in chromic 

 acid alone. (Simple hardening in spirit also answers 

 in many cases fairly well.) After having been a 

 fortnight in this mixture, the piece of skin is trans- 

 ferred to strong spirit, and after two or three days 



