STUDY OF THE GENICULA OF CORALLINE. 35 



parts in a greater or less degree; but the reaction is most vivid in the 

 epidermal layer and in the cellwall of the subepidermal cells. The 

 genicular portion proper retains ;i bright red colour. Treated with 

 chloriodide of zinc, the epidermal laver assumes a deep yellow colour 

 and the subepidermal cells have their cellwall stained in faint violet. 

 The primary cellwall in every part becomes stained in violet. The 

 middle lamella remains unchanged. The starch grains in the 

 medullary cells assume a chestnut brown colour, while the cellcontents 

 in the subepidermal cells change only to yellow. The genicular por- 

 tion proper stains in deep brownish yellow. The gélose reaction by 

 ruthenium red is seen without treating with hydrochloric acid, but 

 chloriodide of zinc can never act upon the cellwall of the articular cells 

 before the treatment with the acid. 



Before treatment with hydrochloric acid the cellwall gives no 

 reaction either by strong caustic potash or by potassium iodide iodine 

 and sulphuric acid. 



After boiling the sections in 2% hydrochloric acid for a few 

 minutes, washing thoroughly in water, and again boiling in 2% 

 caustic potash, a few drops of chloriodide of zinc were poured in under 

 the coverglass; epidermal layer stained in bright yellow and the cell- 

 wall of the subepidermal cells in a slight degree. The cellwall of the 

 articular cells gains a yellow tint, but the middle lamella of these, 

 which was much swollen during the process, stains in pale violet. 

 The connecting plates between the cells become exceedingly clear: the 

 central portion of them staining in deep brown and the border in 

 bright yellow. A preparation boiled in like manner was treated in 

 ruthenium red. The middle lamella, if not swollen too much, is 

 stained in some degree, theswollen portion remaining unstained : the 

 connecting plates assume a red colour and their central portions in a 

 «reater decree. 



