IN VEGETABLE BIOLOGT. 243 



•Ffy* Xylem fairly good reaction, hard bast very faint ditto, 

 soft bast and cortex not coloured. 



Bosa canina. Xylem and hard bast react well, pith and cortex 

 faintly, but cuticularized layers of the latter well. 



Sectious not placed in the fluid behaved in the same way. 



Expee. IV. Sections of Fig, Ash, and Elm placed in pancreatic 

 fluid for 60 hours, when tested with Copper Sulphate and 

 Caustic Potash, gave the same reactions as did fresh sections. 



Expeb. V. Peptic fluid : 60 hours (X). 



Fig. Same reaction as with sections treated with pancreatic 

 fluid, except that the taint colour in the hard bast of the latter 

 was not apparent. 



Ash. As with sections treated with pancreatic fluid. 



Arnndo Fhragmites. Ditto. 



Veg .-Marroiv (stem). Xylem good reaction, none elsewhere, 

 xcept very faintly in bast, and fresh sections behave similarly. 



Expee. VI. Peptic fluid : 60 hours (E). 



Ash. Reaction the same as after the pancreatic fluid. 



Fig. Ditto. 



Bosa canina. Ditto. 



Aran do Fhragmites. Ditto. 



Veg. -Marrow. The walls giving the Xanthoproteic reaction 

 gave Easpail's. So did those which had not been in the fluid. 



Expeb. VII. Peptic fluid : 61 hours (M). 



Fig. Faint reaction in xylem alone: unpeptonized sections 

 ditto. 



Arundo Fhragmites. Parts giving (X) and (E) gave this iu 

 precisely the same way as did fresh sections. 



Veg. -Mar row. As with (X) and (E), and to the same effect 

 as fresh sections. 



* 



It seemed unnecessary to further repeat these observations, as 

 in twenty-three cases, after the action of proteolyzing fluids 

 during from 60 to 76 hours*, the proteid tests were got with the 

 same ease and distinctness after as before treatment. One must 

 hence conclude that if protein really exist in these walls it must 

 be present in some unpeptonizable form. 



# In some other experiments, which m»y be passed over without further 

 reference, the action (pancreatic) was continued for 146 hours, after which 

 normal reactions were still obtained (Maize, Bosa canina, Iso'etes lacastris). 



