

242 MH. S. LE M. MOORE' 8 STUDIES 



quite conceivable that a peptonizable proteid might combine with 



some ingredient or ingredients of the wall to form an unpepto- 



nizable compound, and this without losing its property of yielding 



proteid reactions. The presumption is, of course, the other way ; 



nevertheless the possibility hinted at should not be allowed to 

 pass out of view. 



In this part of the research reliance was mainly placed upon 

 Millon's, Kaspail's, and the Xanthoproteic reactions, Copper 

 Sulphate and Caustic Potash being a tiresome and uncertain 

 microchemical test. These reactions will be denoted by (M), 

 (R), and (X) respectively. The peptonizing fluids were an 

 artificial gastric juice made with a pepsin which gave a good 

 biuret reaction with chopped meat, and a pancreatic fluid in 

 the form of Fairchild's powders, consisting of a pancreatic ex- 

 tract, five grams of which are charged with thrice the quantity of 

 sodium bicarbonate. In these cases no very exhaustive exami- 

 nation of the various tissues was made, only those reacting in an 

 obvious manner being here referred to. It was also thought 

 better to ring the changes on a few, rather than to trust in the 

 few reactions of a larger number of types. 



Expee. I. Pancreatic fluid. Time 76 hours (E). 



Ash (stem). Xylem and hard bast brown-pink ; walls of soft 

 bast not coloured. 



Elm (stem). "Walls of xylem and phloem brown-piuk: of 

 cortex yellow-red. 



Fig (stem). Xylem and pith-walls brown-pink ; bast un- 

 coloured. 



Sections of fresh tissues gave the same results precisely. 



Expee. II. As before. Time 60 hours. 



Rosa canina (stem). Xylem, pith, hard bast brown-pink; 

 cortex yellower, soft bast uncoloured. 



Arundo Rhragmites (rhizome). Cells of sclerotized ground- 

 tissue, including the thick-walled endoderm, and xylem elements 

 brown-pink ; no colour in phloem and rest of ground-tissue. 



And fresh tissues react similarly. 



Exper. III. Pancreatic fluid : 60 hours (X). 



Ash. Xylem faint reaction, hard bast a good one, soft bast 

 uncoloured. 



