338 THE AMERICAN MONTHLY [Nov. 



is the best way to see the connecting filaments between 

 the cells of Malpighi's mucous body. 



Uriion of the epidermis and the dermis. — Take a shred 

 of skin from a region where the epidermic layer is thin, 

 and macerate it in the following : water, 150 grras. ; 

 acetic acid, 1 grm. In from 24 to 48 hours, seize, with 

 the forceps, an edge of the epidermic layer and tear it off 

 gently. You will thus obtain the epidermic" plates ; ex- 

 amine the lower surface. 



The der^nis. — To the preceding methods by which this 

 layer may be studied the following should be added: 



Elastic fibres. — A section obtained after the action of 

 alcohol is deeply colored by picro-carmine, washed, 

 mounted in a mixture of glycerine, picric acid and formic 

 acid. Also stain a section deeply with eosine and mount 

 in a drop of 40 per cent potash solution. Also section 

 as before, place in the following stain for 24 hours : 

 dahlia grms. 0.2 ; alcohol, 5 grms. ; distilled water, 5 

 grms. • dissolve and add : nitric acid, 2 grms. ; water, 

 18 grms. ; alcohol, 10 grms. After staining, treat with 

 acetic acid and mount in balsam or in glycerine. In the 

 last mentioned the preparation will not keep. 



Cells of the dermis. — Treat a section by Erlich's method 

 for granule cells. 



Cells. — A piece 1 or 2 mm. square is put in filtered 

 fresh lemon juice. In 10 minutes wash rapidly and put 

 in a few c. c. of gold chloride. Wash again, and reduce 

 in the i formic acid for 24 houts. Harden in gum and 

 alcohol ; mount the sections in glycerine. 



Blood vessels. — Inject an amputated human finger. 

 Treat a piece of skin from the tip with bichromate, gum 

 and alcohol. Section perpendicularly to the surface ; 

 alum carmine, balsam. 



Lymphatic vessels. — ^A hypodermic syringe with a 

 short, fine-pointed needle is filled with the soluble blue ; 

 pierce the skin obliquely and inject. If an elevation is 



